Cannabis
Cannabis is the most commonly used illicit drug. In Norway, the cannabis extract Sativex is an approved medication for patients with multiple sclerosis (MS). It is also possible to get special approval for medical cannabis on a case-by-case basis (godkjenningsfritak).
Dosage:
60–100 mg of plant material
60–100 mg of plant material
Duration:
2–4 hours (inhaled)
4–10 hours (consumed orally)
2–4 hours (inhaled)
4–10 hours (consumed orally)
Risks:
Acute toxicity: ⦿⦾⦾⦾⦾ (Very low risk)
Long-term toxicity: ⦿⦿⦾⦾⦾ (Low risk)
Dependence: ⦿⦿⦿⦾⦾ (Moderate risk)
Cognitive problems: ⦿⦿⦿⦾⦾ (Moderate risk)
Undesirable events: ⦿⦿⦾⦾⦾ (Low risk)
Interactions: ⦿⦿⦾⦾⦾ (Low risk)
Scroll down for the full risk profile.
Acute toxicity: ⦿⦾⦾⦾⦾ (Very low risk)
Long-term toxicity: ⦿⦿⦾⦾⦾ (Low risk)
Dependence: ⦿⦿⦿⦾⦾ (Moderate risk)
Cognitive problems: ⦿⦿⦿⦾⦾ (Moderate risk)
Undesirable events: ⦿⦿⦾⦾⦾ (Low risk)
Interactions: ⦿⦿⦾⦾⦾ (Low risk)
Scroll down for the full risk profile.
Cannabis (Cannabis sativa) is a widely distributed plant whose female flowers contain a range of compounds. Two of these, delta-9-tetrohydrocannabinol (THC) and cannabidiol (CBD), have been extensively researched. Cannabis the most widely used illicit drug worldwide, being illegal in most countries. Its use for medical purposes is regulated in several countries, and its recreational use is tolerated or even regulated in some regions. In Norway, the cannabis extract Sativex is an approved medication for patients with multiple sclerosis (MS). It is also possible to get special approval for medical cannabis on a case-by-case basis (godkjenningsfritak).
Cannabis is normally smoked or vaporized, but may also be ingested via foods ("edibles") or drinks infused with cannabis. The drug typically produces feelings of relaxation, although mild confusion is not uncommon. Different plants can yield somewhat different effects, ranging from calming and sedative to stimulating and psychedelic. Cannabis tends to increase appetite, and may also enhance sensory impressions like flavors, colors, and sounds.
Despite cannabis' low toxicity, frequent use can lead to mild cognitive impairment, and more extreme use can lead to chronic nausea and vomiting. Both of these symptoms normally go away some time after discontinued use. Roughly 10% of cannabis users become addicted to the drug. In individuals who are predisposed to psychotic disorders like schizophrenia, cannabis use may trigger or worsen their condition. The risk of dependence and psychosis is associated mainly with use of very strong cannabis containing high amounts of THC and low amounts of CBD.
Cannabis is normally smoked or vaporized, but may also be ingested via foods ("edibles") or drinks infused with cannabis. The drug typically produces feelings of relaxation, although mild confusion is not uncommon. Different plants can yield somewhat different effects, ranging from calming and sedative to stimulating and psychedelic. Cannabis tends to increase appetite, and may also enhance sensory impressions like flavors, colors, and sounds.
Despite cannabis' low toxicity, frequent use can lead to mild cognitive impairment, and more extreme use can lead to chronic nausea and vomiting. Both of these symptoms normally go away some time after discontinued use. Roughly 10% of cannabis users become addicted to the drug. In individuals who are predisposed to psychotic disorders like schizophrenia, cannabis use may trigger or worsen their condition. The risk of dependence and psychosis is associated mainly with use of very strong cannabis containing high amounts of THC and low amounts of CBD.
Please see our 10 general rules for sensible drug use. You should also be mindful of the following:
- Avoid using cannabis if you or anyone in your close family suffer from a psychotic disorder, like schizophrenia. It is also strongly recommended that you quit using cannabis if you find that you easily become paranoid or get delusional thoughts while high.
- Avoid using cannabis daily. Frequent use can negatively impact memory and attention span, and can also lead to addiction and/or mental health problems in some people.
- Be careful with strong cannabis strains, as these are associated with a higher risk of mental health problems and addiction compared to milder strains.
- Avoid mixing cannabis with tobacco, which is not only harmful, but also greatly increases your risk of addiction. The combined effects of both drugs can also be unpleasant. If possible, use a vaporizer or a pipe instead of smoking joints. Cannabis can also be eaten, but beware that this produces a delayed and much longer-lasting effect.
- Do not use cannabis in an unsafe place or with people you do not feel comfortable around. If you become confused or anxious, it may help to find a quiet place to relax, breathe, and listen to calm music.
- Be careful with mixing cannabis and alcohol. This can produce a powerful combined effect that includes dizziness and nausea. If you do decide to combine, take the cannabis before you start drinking, and drink less than you normally would.
- Avoid combining cannabis with psychedelics. This can lead to confusion and anxiety, and may increase the risk of a drug-increased psychosis.
We employ a five-step risk scale with values ranging from "very low" to "very high" within six categories: Acute toxicity, Long-term toxicity, Dependence, Cognitive problems, Unpleasant events, and Interactions.
These values are based on qualitative reviews of available knowledge, and should only be viewed as guidelines. They are also relative, so a score of "very low risk" does not mean the substance is risk-free. The scale assumes users are normal, healthy individuals; beware that even drugs which are well-tolerated by most people may nevertheless be harmful to some users. It also assumes normal use patterns; that is, if a given drug is only harmful when used in a certain way, yet is almost never used in that way, then the drug will be considered less harmful compared to a similar drug which is commonly used in a harmful way.
ACUTE TOXICITY
⦿⦾⦾⦾⦾ (Very low risk)
The risk of overdosing on cannabis is among the lowest of any commonly used drug. According to the World Health Organization (WHO), it is practically impossible to take a lethal dose of cannabis in the form of plant matter, i.e. by smoking/vaporizing or eating. However, this does not necessarily apply to extremely potent concentrates (e.g. oil, "shatter"), and some children have needed intensive care after unknowingly eating very strong cannabis products.
LONG-TERM TOXICITY
⦿⦿⦾⦾⦾ (Low risk)
Cannabis appears have low toxicity. Some heavy users of very potent cannabis show signs of structural deviations in certain areas of the brain, but this is not observed in equally heavy users of averagely-potent cannabis. Habitual use of cannabis by teens is associated with abnormal distribution of white and grey brain matter later in life, albeit to a lesser degree than is observed with habitual alcohol use. While some studies have found an increased risk of heart attack in cannabis users, other studies have not found this, and some have even found that cannabis use is associated with a higher rate of survival in heart attack victims. Some studies have found a weak link between smoking cannabis and increased risk of certain cancers, but these studies have generally not been able to control for tobacco use. In general, inhaling the fumes of any burning plant matter can lead to respiratory problems, and it is generally recommended to take cannabis in the form of a vaporizer or edible products rather than to smoke joints.
DEPENDENCE
⦿⦿⦿⦾⦾ (Moderate risk)
Roughly 1 out of every 10 cannabis users develop an addiction to cannabis. This rate is about 1.5 times higher (1 out of every 6) in those who start using before the age of 15; however, it is not clear whether this is because an early debut leads to a greater risk of addiction, or whether those who are already predisposed to addiction are more likely to start experimenting early. Cannabis dependency tends to be less challenging to break than more strongly addictive drugs like cocaine or heroin, but some users nevertheless experience very uncomfortable withdrawal symptoms. The risk of both dependence and withdrawal symptoms appears to have a genetic component that could play a role in mediating the effects of cannabis in the user's brain. The ratio of CBD to THC also appears to play a role, with low-CBD/high-THC cannabis being linked to a higher risk of dependence, as well as a different effect on certain brain regions, compared to high CBD strains.
COGNITIVE PROBLEMS
⦿⦿⦿⦾⦾ (Moderate risk)
Cannabis users have roughly twice the risk of psychotic disorders compared to the population average. People with psychotic disorders who use cannabis also tend to develop symptoms roughly 3 years earlier than non-users. It is still unclear whether cannabis actually causes psychotic disorders, or if people who already have a psychotic disorder (or are predisposed thereto) are just more likely to start using cannabis in the first place. This picture is further complicated by the fact that people with psychotic disorders tend to use and experiment with drugs at a higher rate, and that illicit drug users in general face more mental health risk factors, than the average population. The current consensus among researchers seems to be that psychotic disorders are unlikely to be caused by cannabis use alone, but that cannabis use may be one of several stressors which collectively trigger such disorders in vulnerable individuals. Moreover, the fact that psychotic disorders are not more prevalent in countries where cannabis potency and use have sharply increased in recent years, may indicate a low risk contribution on the part of cannabis; alternatively, it could imply that most susceptible individuals quit by themselves before they develop a psychotic disorder, possibly because they experience more unpleasant symptoms while high.
The vast majority of cannabis users, about 98%, never experience a psychosis. The risk seems to apply predominantly to cannabis users who have a recent family history of psychotic disorders and consume mostly high-THC/low-CBD cannabis at a very high rate. However, taking a high dose of very potent cannabis may nevertheless produce symptoms similar to a psychosis, including paranoia, delusions, or hallucinations. Although this may be very frightening, it normally goes away after a few hours at most. If you experience this, it may help to find yourself a safe spot where you can focus on breathing calmly, ideally with a trusted friend nearby who can help "anchor" you to reality.
There is little to suggest that cannabis use leads to long-lasting or permanent cognitive impairment, and twin studies have not established any link between early cannabis use and low adult IQ. In the short term, however, cannabis' effects (whether immediate effects, hangover effects after large doses, or withdrawal symptoms after discontinued heavy use) can negatively affect a range of cognitive functions, including memory, attention, and learning ability. Researchers have found no cognitive impairment among people who use cannabis twice a month or less, while frequent users on average score somewhat lower than non-users on cognitive tests. After users quit, any cognitive impairment symptoms that were present during use go away within a few days or weeks, depending on the extent of use prior to quitting. Research on younger cannabis users has not found evidence of cognitive impairment in studies where the tests where administered more than 72 hours after subjects last used cannabis. Frequent cannabis use can cause small amounts of THC to linger in the bloodstream for extended periods, but users quickly develop a tolerance to these low levels. This should not be confused with tolerance to immediate effects, which takes much longer to develop. This means that using cannabis several times a day can lead to cognitive impairment as a result of spending much of the day in a sustained high.
It should be noted that high-CBD cannabis appears to cause much less cognitive impairment than low-CBD varieties. High-CBD cannabis is also not associated with any significantly higher risk of psychosis, and CBD in large doses appear to have an antipsychotic effect. Concerns related to cognitive function and mental health thus apply mainly to low-CBD/high-THC cannabis, which includes the most common varieties in circulation today.
UNDESIRABLE EVENTS
⦿⦿⦾⦾⦾ (Low risk)
In general, cannabis tends to calm users and make them less aggressive; however, feelings of paranoia or delusional thinking can lead some people to act out in fear and behave in irrational ways, which may be unsettling or embarrassing to others in the moment or themselves in hindsight. Moreover, high doses can produce a disorienting and sedative effect, which may leave the user vulnerable to accidents or exploitation in situations where such risks are present.
Due to its very distinct smell, the risk of being caught by police when using cannabis is very great, likely greater than for any other drug. It also remains detectable in urine and blood samples for much longer than other drugs: after long periods of heavy use, cannabis is detectable for up to several months in urine and at least a few weeks in blood. Being caught using cannabis can, in additon to punishment and a permanent police record, even lead to seizure of one's driver's license if one admits to using cannabis more than a few times per year. This latter practice is due to fears that heavy use causes THC to accumulate in the bloodstream in quantities that exceed the punishment limit as defined by road safety laws (vegtrafikkloven). Although this is theoretically possible in cases of long-term, frequent use, it is still a matter of controversy whether these cumulative levels pose any danger in traffic situations, given that frequent users develop a tolerance to THC. Also note that if a patient admits to a medical practitioner (e.g. their physician or therapist) about their frequent use of cannabis, and the medical practitioner fears that this might impact the patient's ability to safely operate a motor vehicle, then they are under a legal duty to report it to the police, who may then decide to seize the patient's driver's license.
INTERACTIONS
⦿⦿⦾⦾⦾ (Low risk)
Cannabis appears to pose a low risk of direct harm when combined with other drugs. Nevertheless, combining cannabis with psychedelics or dissociatives can enhance their disorienting effect, thereby increasing the risk of confusion, anxiety, and psychotic reactions. This effect appears to be more common when the cannabis is consumed first, and with very potent forms, whereas the risk appears lower when less potent cannabis is consumed in small amounts after the effects of the psychedelic or dissociative drug have had time to stabilize.
Combining cannabis with alcohol is not especially problematic in and of itself, and there is some research indicating that certain phytochemicals present in cannabis can protect the liver and brain against some of alcohol's damaging effects. It does, however, matter what order the two drugs are taken in, and at what doses. Using cannabis before drinking mainly leads to a slower absorption of alcohol into the bloodstream. But if alcohol is consumed before cannabis, the alcohol causes THC levels in the blood to be higher than they normally would be, which means the cannabis effects can be much stronger than anticipated. It is not uncommon to experience confusion, disorientation, dizziness, and vomiting if one smokes cannabis (especially potent forms with low CBD content) after drinking a large amount of alcohol.
Cannabis in combination with central nervous stimulants can lead to increased heart rate, which suggests that people with heart problems should be cautious about such combinations, especially in the case of potent cannabis with low CBD content. Using cannabis in combination with medications that reduce blood pressure, or by people who already suffer from low blood pressure, is also not advisable, as this can lead to a rapid drop in blood pressure.
These values are based on qualitative reviews of available knowledge, and should only be viewed as guidelines. They are also relative, so a score of "very low risk" does not mean the substance is risk-free. The scale assumes users are normal, healthy individuals; beware that even drugs which are well-tolerated by most people may nevertheless be harmful to some users. It also assumes normal use patterns; that is, if a given drug is only harmful when used in a certain way, yet is almost never used in that way, then the drug will be considered less harmful compared to a similar drug which is commonly used in a harmful way.
ACUTE TOXICITY
⦿⦾⦾⦾⦾ (Very low risk)
The risk of overdosing on cannabis is among the lowest of any commonly used drug. According to the World Health Organization (WHO), it is practically impossible to take a lethal dose of cannabis in the form of plant matter, i.e. by smoking/vaporizing or eating. However, this does not necessarily apply to extremely potent concentrates (e.g. oil, "shatter"), and some children have needed intensive care after unknowingly eating very strong cannabis products.
LONG-TERM TOXICITY
⦿⦿⦾⦾⦾ (Low risk)
Cannabis appears have low toxicity. Some heavy users of very potent cannabis show signs of structural deviations in certain areas of the brain, but this is not observed in equally heavy users of averagely-potent cannabis. Habitual use of cannabis by teens is associated with abnormal distribution of white and grey brain matter later in life, albeit to a lesser degree than is observed with habitual alcohol use. While some studies have found an increased risk of heart attack in cannabis users, other studies have not found this, and some have even found that cannabis use is associated with a higher rate of survival in heart attack victims. Some studies have found a weak link between smoking cannabis and increased risk of certain cancers, but these studies have generally not been able to control for tobacco use. In general, inhaling the fumes of any burning plant matter can lead to respiratory problems, and it is generally recommended to take cannabis in the form of a vaporizer or edible products rather than to smoke joints.
DEPENDENCE
⦿⦿⦿⦾⦾ (Moderate risk)
Roughly 1 out of every 10 cannabis users develop an addiction to cannabis. This rate is about 1.5 times higher (1 out of every 6) in those who start using before the age of 15; however, it is not clear whether this is because an early debut leads to a greater risk of addiction, or whether those who are already predisposed to addiction are more likely to start experimenting early. Cannabis dependency tends to be less challenging to break than more strongly addictive drugs like cocaine or heroin, but some users nevertheless experience very uncomfortable withdrawal symptoms. The risk of both dependence and withdrawal symptoms appears to have a genetic component that could play a role in mediating the effects of cannabis in the user's brain. The ratio of CBD to THC also appears to play a role, with low-CBD/high-THC cannabis being linked to a higher risk of dependence, as well as a different effect on certain brain regions, compared to high CBD strains.
COGNITIVE PROBLEMS
⦿⦿⦿⦾⦾ (Moderate risk)
Cannabis users have roughly twice the risk of psychotic disorders compared to the population average. People with psychotic disorders who use cannabis also tend to develop symptoms roughly 3 years earlier than non-users. It is still unclear whether cannabis actually causes psychotic disorders, or if people who already have a psychotic disorder (or are predisposed thereto) are just more likely to start using cannabis in the first place. This picture is further complicated by the fact that people with psychotic disorders tend to use and experiment with drugs at a higher rate, and that illicit drug users in general face more mental health risk factors, than the average population. The current consensus among researchers seems to be that psychotic disorders are unlikely to be caused by cannabis use alone, but that cannabis use may be one of several stressors which collectively trigger such disorders in vulnerable individuals. Moreover, the fact that psychotic disorders are not more prevalent in countries where cannabis potency and use have sharply increased in recent years, may indicate a low risk contribution on the part of cannabis; alternatively, it could imply that most susceptible individuals quit by themselves before they develop a psychotic disorder, possibly because they experience more unpleasant symptoms while high.
The vast majority of cannabis users, about 98%, never experience a psychosis. The risk seems to apply predominantly to cannabis users who have a recent family history of psychotic disorders and consume mostly high-THC/low-CBD cannabis at a very high rate. However, taking a high dose of very potent cannabis may nevertheless produce symptoms similar to a psychosis, including paranoia, delusions, or hallucinations. Although this may be very frightening, it normally goes away after a few hours at most. If you experience this, it may help to find yourself a safe spot where you can focus on breathing calmly, ideally with a trusted friend nearby who can help "anchor" you to reality.
There is little to suggest that cannabis use leads to long-lasting or permanent cognitive impairment, and twin studies have not established any link between early cannabis use and low adult IQ. In the short term, however, cannabis' effects (whether immediate effects, hangover effects after large doses, or withdrawal symptoms after discontinued heavy use) can negatively affect a range of cognitive functions, including memory, attention, and learning ability. Researchers have found no cognitive impairment among people who use cannabis twice a month or less, while frequent users on average score somewhat lower than non-users on cognitive tests. After users quit, any cognitive impairment symptoms that were present during use go away within a few days or weeks, depending on the extent of use prior to quitting. Research on younger cannabis users has not found evidence of cognitive impairment in studies where the tests where administered more than 72 hours after subjects last used cannabis. Frequent cannabis use can cause small amounts of THC to linger in the bloodstream for extended periods, but users quickly develop a tolerance to these low levels. This should not be confused with tolerance to immediate effects, which takes much longer to develop. This means that using cannabis several times a day can lead to cognitive impairment as a result of spending much of the day in a sustained high.
It should be noted that high-CBD cannabis appears to cause much less cognitive impairment than low-CBD varieties. High-CBD cannabis is also not associated with any significantly higher risk of psychosis, and CBD in large doses appear to have an antipsychotic effect. Concerns related to cognitive function and mental health thus apply mainly to low-CBD/high-THC cannabis, which includes the most common varieties in circulation today.
UNDESIRABLE EVENTS
⦿⦿⦾⦾⦾ (Low risk)
In general, cannabis tends to calm users and make them less aggressive; however, feelings of paranoia or delusional thinking can lead some people to act out in fear and behave in irrational ways, which may be unsettling or embarrassing to others in the moment or themselves in hindsight. Moreover, high doses can produce a disorienting and sedative effect, which may leave the user vulnerable to accidents or exploitation in situations where such risks are present.
Due to its very distinct smell, the risk of being caught by police when using cannabis is very great, likely greater than for any other drug. It also remains detectable in urine and blood samples for much longer than other drugs: after long periods of heavy use, cannabis is detectable for up to several months in urine and at least a few weeks in blood. Being caught using cannabis can, in additon to punishment and a permanent police record, even lead to seizure of one's driver's license if one admits to using cannabis more than a few times per year. This latter practice is due to fears that heavy use causes THC to accumulate in the bloodstream in quantities that exceed the punishment limit as defined by road safety laws (vegtrafikkloven). Although this is theoretically possible in cases of long-term, frequent use, it is still a matter of controversy whether these cumulative levels pose any danger in traffic situations, given that frequent users develop a tolerance to THC. Also note that if a patient admits to a medical practitioner (e.g. their physician or therapist) about their frequent use of cannabis, and the medical practitioner fears that this might impact the patient's ability to safely operate a motor vehicle, then they are under a legal duty to report it to the police, who may then decide to seize the patient's driver's license.
INTERACTIONS
⦿⦿⦾⦾⦾ (Low risk)
Cannabis appears to pose a low risk of direct harm when combined with other drugs. Nevertheless, combining cannabis with psychedelics or dissociatives can enhance their disorienting effect, thereby increasing the risk of confusion, anxiety, and psychotic reactions. This effect appears to be more common when the cannabis is consumed first, and with very potent forms, whereas the risk appears lower when less potent cannabis is consumed in small amounts after the effects of the psychedelic or dissociative drug have had time to stabilize.
Combining cannabis with alcohol is not especially problematic in and of itself, and there is some research indicating that certain phytochemicals present in cannabis can protect the liver and brain against some of alcohol's damaging effects. It does, however, matter what order the two drugs are taken in, and at what doses. Using cannabis before drinking mainly leads to a slower absorption of alcohol into the bloodstream. But if alcohol is consumed before cannabis, the alcohol causes THC levels in the blood to be higher than they normally would be, which means the cannabis effects can be much stronger than anticipated. It is not uncommon to experience confusion, disorientation, dizziness, and vomiting if one smokes cannabis (especially potent forms with low CBD content) after drinking a large amount of alcohol.
Cannabis in combination with central nervous stimulants can lead to increased heart rate, which suggests that people with heart problems should be cautious about such combinations, especially in the case of potent cannabis with low CBD content. Using cannabis in combination with medications that reduce blood pressure, or by people who already suffer from low blood pressure, is also not advisable, as this can lead to a rapid drop in blood pressure.
DOSAGE
The easiest way to reliably dose cannabis is by smoking it, since the effects appear very quickly after inhalation. If you are not experienced with cannabis, or you do not know the strength of the cannabis you are about to smoke, it is best to only take a few puffs to begin with and then wait roughly 20 minutes before taking more.
OVERDOSE
It does not appear practically possible to lethally overdose on cannabis. However, taking too much in a short time can lead to anxiety, panic attacks, and psychosis-like reactions. Such overdoses are mostly seen after ingesting cannabis edibles or beverages, since the delayed effects make it easier to accidentally ingest too much at once, and are comparatively rare when the cannabis is smoked instead.
FORM
Cannabis is most commonly sold in the form of either dried flower buds (marijuana, weed) or as a resinous mass (hashish). Depending on the way hashish is produced, it can end up as a greenish-brown powdery substance pressed into a brittle plate, or as a very dark brown, sticky mass rolled into a lump, or anything in between. More recently, there has been a rise in the use of cannabis extracts like oils and waxes (dabs, shatter), as well as candies and other foods (edibles) infused with such extracts. Note that cannabis edibles can be extremely potent, and when compared to smoked cannabis, the effects come up much more slowly and produce a slightly different high.
ROUTE OF ADMINISTRATION
Cannabis is most commonly smoked, although the exact form of smoking tends to vary by region. In Norway and much of Europe, marihuana or hashish is usually mixed with tobacco and rolled into a cigarette (joint, spliff): in the US, by contrast, pure marihuana is more common. The combined effect of cannabis and tobacco can be unpleasant to some users, with a higher risk of confusion and anxiety than cannabis alone; this seems especially to occur in people who are not habitual tobacco users.
Besides smoking, cannabis can also be vaporized. A growing number of users prefer this method, which is less irritating to the respiratory system and very probably less harmful to one's health overall. Many users also take cannabis orally, either by eating cannabis-infused foods (edibles) or tea. This produces a much stronger, longer-lasting, and slightly different high than smoked cannabis. Edibles in particular can take several hours to come into full effect, which makes it much easier to accidentally eat too much at the outset, potentially resulting in a very unpleasant experience.
The easiest way to reliably dose cannabis is by smoking it, since the effects appear very quickly after inhalation. If you are not experienced with cannabis, or you do not know the strength of the cannabis you are about to smoke, it is best to only take a few puffs to begin with and then wait roughly 20 minutes before taking more.
OVERDOSE
It does not appear practically possible to lethally overdose on cannabis. However, taking too much in a short time can lead to anxiety, panic attacks, and psychosis-like reactions. Such overdoses are mostly seen after ingesting cannabis edibles or beverages, since the delayed effects make it easier to accidentally ingest too much at once, and are comparatively rare when the cannabis is smoked instead.
FORM
Cannabis is most commonly sold in the form of either dried flower buds (marijuana, weed) or as a resinous mass (hashish). Depending on the way hashish is produced, it can end up as a greenish-brown powdery substance pressed into a brittle plate, or as a very dark brown, sticky mass rolled into a lump, or anything in between. More recently, there has been a rise in the use of cannabis extracts like oils and waxes (dabs, shatter), as well as candies and other foods (edibles) infused with such extracts. Note that cannabis edibles can be extremely potent, and when compared to smoked cannabis, the effects come up much more slowly and produce a slightly different high.
ROUTE OF ADMINISTRATION
Cannabis is most commonly smoked, although the exact form of smoking tends to vary by region. In Norway and much of Europe, marihuana or hashish is usually mixed with tobacco and rolled into a cigarette (joint, spliff): in the US, by contrast, pure marihuana is more common. The combined effect of cannabis and tobacco can be unpleasant to some users, with a higher risk of confusion and anxiety than cannabis alone; this seems especially to occur in people who are not habitual tobacco users.
Besides smoking, cannabis can also be vaporized. A growing number of users prefer this method, which is less irritating to the respiratory system and very probably less harmful to one's health overall. Many users also take cannabis orally, either by eating cannabis-infused foods (edibles) or tea. This produces a much stronger, longer-lasting, and slightly different high than smoked cannabis. Edibles in particular can take several hours to come into full effect, which makes it much easier to accidentally eat too much at the outset, potentially resulting in a very unpleasant experience.
MECHANISM OF ACTION
Cannabis contains several cannabinoids, of which delta-9-tetrahydrocannabinol (THC) seems to account for the majority of the drug effects. Cannabinoids work on the cannabinoid receptor system in the brain and body, where they imitate the body's own endocannabinoids, including anandamide and 2-AG. These receptors can only be activated by THC to a limited degree, since THC is only a partial agonist. This effectively means that cannabinoid receptors get saturated with THC at a certain dose, resulting in a ceiling effect where no additional effects are felt even if one takes more of the drug, and one is shielded from toxic overdose. However, many synthetic cannabinoids (spice) are full agonists, and thus lack this ceiling effect. This makes them significantly more dangerous than cannabis, and use of synthetic cannabis has indeed led to several confirmed deaths.
While THC accounts for most of the psychoactive effects, a different compound, cannabidiol (CBD), counteracts many of THC's more unpleasant side-effects like anxiety, memory problems, and paranoia. Controlled studies have also shown CBD to have an antipsychotic effect comparable to approved antipsychotic medications, and cannabis with a high CBD content is not associated with an increased risk of psychosis. THC and CBD are both made from the same precursor compound, cannabigerol (CBG), of which the plant has only a limited amount, resulting in a trade-off between the amount of each drug produced. This means that a given plant's THC-to-CBD ratio is a factor if its strength, i.e. that potent strains high in THC necessarily contain little CBD. Because prohibition incentivizes growers to produce the most potent cannabis possible (in order to maximize profits while minimizing risks related to transport and storage), and since several countries with legal cannabis markets allow the sale of very potent strains, there has been a trend in recent years towards cannabis with very high THC and very little CBD.
SUBJECTIVE EFFECTS
When cannabis is smoked or vaporized, its effects set in very quickly, often within a few minutes of inhalation. They then taper off again after 2–3 hours and are usually completely gone after 6 hours. In the body, THC is metabolized into the psychoactive metabolite 11-hydroxy-THC, and then to inactive THC acid. Eating cannabis results in higher levels of 11-hydroxy-THC than smoking does, which likely accounts for why the effects of edibles are often described as qualitatively different and more psychedelic.
A mild cannabis high normally leads to feelings of satisfaction and bodily comfort, and many users report a sense of mental calm or quieting down of one's mind. At higher doses, thoughts can become more active and chaotic, and feelings of confusion or anxiety are not uncommon. The cannabis experience has certain psychedelic qualities to it: mundane things can appear absurd or comical, lights and sounds appear more intense, and music is often perceived as more interesting or engaging. Some also experience a mild form of synesthesia (senses blending into one another, so that one sees sounds, hears smells, etc.) that is reminiscent of psychedelics. Cannabis can also enhance culinary experiences and often leads to increased appetite (munchies). Some people find cannabis erotic or sexually stimulating, likely due to its being at once calming, stimulating, and vasodilating (expanding blood vessels); others, meanwhile, find it has the opposite effect, making them less interested in sex or other forms of intimacy.
SIDE-EFFECTS
Common side-effects during a cannabis high include high heart rate or blood pressure, mild headache, dry mouth, bloodshot eyes, dilated pupils, and impaired short-term memory. Coordination and reaction times are both impared, albeit to a lesser degree than by alcohol. Holding a conversation thread running often becomes more challenging, especially with more potent strains, and many find they become less talkative than usual when high.
Cannabis does not produce a strong hangover. Still, it is not uncommon to feel lethargic and a bit cognitively slow the day after. This may be because cannabis interferes with the body's sleep cycle and hence reduces sleep quality, but may also be due to short-term inhibition of the brain's dopamine response.
In rare cases, very high consumption of cannabis or cannabis products (including CBD) can lead to a condition called cannabis hyperemesis syndrome, marked by extreme nausea, abdominal pain, and sudden bouts of violent vomiting. Showering one's chest and solar plexus with warm water offers some relief, as does the use of chilli ointments on the skin, but by far the most effective remedy is to quit using cannabis for an extened period. Although the mechanism behind this syndrome is still unknown, there is some speculation that cannabis' anti-nausea properties might produce paradoxical effects in cases of chronic and extreme overuse.
Cannabis contains several cannabinoids, of which delta-9-tetrahydrocannabinol (THC) seems to account for the majority of the drug effects. Cannabinoids work on the cannabinoid receptor system in the brain and body, where they imitate the body's own endocannabinoids, including anandamide and 2-AG. These receptors can only be activated by THC to a limited degree, since THC is only a partial agonist. This effectively means that cannabinoid receptors get saturated with THC at a certain dose, resulting in a ceiling effect where no additional effects are felt even if one takes more of the drug, and one is shielded from toxic overdose. However, many synthetic cannabinoids (spice) are full agonists, and thus lack this ceiling effect. This makes them significantly more dangerous than cannabis, and use of synthetic cannabis has indeed led to several confirmed deaths.
While THC accounts for most of the psychoactive effects, a different compound, cannabidiol (CBD), counteracts many of THC's more unpleasant side-effects like anxiety, memory problems, and paranoia. Controlled studies have also shown CBD to have an antipsychotic effect comparable to approved antipsychotic medications, and cannabis with a high CBD content is not associated with an increased risk of psychosis. THC and CBD are both made from the same precursor compound, cannabigerol (CBG), of which the plant has only a limited amount, resulting in a trade-off between the amount of each drug produced. This means that a given plant's THC-to-CBD ratio is a factor if its strength, i.e. that potent strains high in THC necessarily contain little CBD. Because prohibition incentivizes growers to produce the most potent cannabis possible (in order to maximize profits while minimizing risks related to transport and storage), and since several countries with legal cannabis markets allow the sale of very potent strains, there has been a trend in recent years towards cannabis with very high THC and very little CBD.
SUBJECTIVE EFFECTS
When cannabis is smoked or vaporized, its effects set in very quickly, often within a few minutes of inhalation. They then taper off again after 2–3 hours and are usually completely gone after 6 hours. In the body, THC is metabolized into the psychoactive metabolite 11-hydroxy-THC, and then to inactive THC acid. Eating cannabis results in higher levels of 11-hydroxy-THC than smoking does, which likely accounts for why the effects of edibles are often described as qualitatively different and more psychedelic.
A mild cannabis high normally leads to feelings of satisfaction and bodily comfort, and many users report a sense of mental calm or quieting down of one's mind. At higher doses, thoughts can become more active and chaotic, and feelings of confusion or anxiety are not uncommon. The cannabis experience has certain psychedelic qualities to it: mundane things can appear absurd or comical, lights and sounds appear more intense, and music is often perceived as more interesting or engaging. Some also experience a mild form of synesthesia (senses blending into one another, so that one sees sounds, hears smells, etc.) that is reminiscent of psychedelics. Cannabis can also enhance culinary experiences and often leads to increased appetite (munchies). Some people find cannabis erotic or sexually stimulating, likely due to its being at once calming, stimulating, and vasodilating (expanding blood vessels); others, meanwhile, find it has the opposite effect, making them less interested in sex or other forms of intimacy.
SIDE-EFFECTS
Common side-effects during a cannabis high include high heart rate or blood pressure, mild headache, dry mouth, bloodshot eyes, dilated pupils, and impaired short-term memory. Coordination and reaction times are both impared, albeit to a lesser degree than by alcohol. Holding a conversation thread running often becomes more challenging, especially with more potent strains, and many find they become less talkative than usual when high.
Cannabis does not produce a strong hangover. Still, it is not uncommon to feel lethargic and a bit cognitively slow the day after. This may be because cannabis interferes with the body's sleep cycle and hence reduces sleep quality, but may also be due to short-term inhibition of the brain's dopamine response.
In rare cases, very high consumption of cannabis or cannabis products (including CBD) can lead to a condition called cannabis hyperemesis syndrome, marked by extreme nausea, abdominal pain, and sudden bouts of violent vomiting. Showering one's chest and solar plexus with warm water offers some relief, as does the use of chilli ointments on the skin, but by far the most effective remedy is to quit using cannabis for an extened period. Although the mechanism behind this syndrome is still unknown, there is some speculation that cannabis' anti-nausea properties might produce paradoxical effects in cases of chronic and extreme overuse.
Cannabis is listed as an illicit drug in Norway.* This means it is punishable by law** to use, possess, sell, manufacture, import, acquire, store, or distribute cannabis without a special license for medical or scientific research purposes. It is also punishable to import and distribute viable cannabis seeds.***
The limit for how much of the drug one can acquire or possess for personal use and still receive only a fine, as opposed to a prison sentence, is currently at 15 grams of plant matter (marihuana or cannabis) or 30 seeds. For importing, the equivalent limit is half as much, i.e. 7.5 grams of plant matter or 15 seeds.
Medical cannabis products require a prescription (reseptgruppe A).
* Narkotikalisten, narkotikaforskriften, legemiddelloven §22** Legemiddelloven §31, §24; straffeloven §231*** Såvareforskriften §28
The limit for how much of the drug one can acquire or possess for personal use and still receive only a fine, as opposed to a prison sentence, is currently at 15 grams of plant matter (marihuana or cannabis) or 30 seeds. For importing, the equivalent limit is half as much, i.e. 7.5 grams of plant matter or 15 seeds.
Medical cannabis products require a prescription (reseptgruppe A).
* Narkotikalisten, narkotikaforskriften, legemiddelloven §22** Legemiddelloven §31, §24; straffeloven §231*** Såvareforskriften §28
1. WHO Expert Committee on Drug Dependence, Delta-9-tetrahydrocannabinol. Critical Review, 2018.
2. Zuurman et al., Biomarkers for the effects of cannabis and THC in healthy volunteers. British Journal of Clinical Pharmacology, 2008.
3. Hall et al., What is the prevalence and risk of cannabis use disorders among people who use cannabis? A systematic review and meta-analysis. Addictive Behaviors, 2020.
4. Mathew et al., Acute cannabis toxicity. Clinical toxicology, 2019.
5. Rigucci et al., Effects of high-potency cannabis on corpus callosum microstructure. Psychological Medicine, 2016.
6. Ravi et al., Associations Between Marijuana Use and Cardiovascular Risk Factors and Outcomes. Annals of Internal Medicine, 2018.
7. Johnson-Sasso et al., Marijuana use and short-term outcomes in patients hospitalized for acute myocardial infarction. PLoS ONE, 2018
8. Abuhasira et al., Cannabis is associated with blood pressure reduction in older adults – A 24-hours ambulatory blood pressure monitoring study. European Journal of Internal Medicine, 2021.
9. Hall, What has research over the past two decades revealed about the adverse health effects of recreational cannabis use? Addiction, 2015.
10. Freeman & Winstock, Examining the profile of high-potency cannabis and its association with severity of cannabis dependence. Psychological Medicine, 2015.
11. Wall et al., Dissociable effects of cannabis with and without cannabidiol on the human brain's resting-state functional connectivity. Journal of Psychopharmacology, 2019.
12. D'Souza et al., Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis. The World Journal of Biological Psychiatry, 2022.
13. Hjorthøi et al., Development Over Time of the Population-Attributable Risk Fraction for Cannabis Use Disorder in Schizophrenia in Denmark. JAMA Psychiatry, 2021.)
14. Sami et al., Psychotic-like experiences with cannabis use predict cannabis cessation and desire to quit: a cannabis discontinuation hypothesis. Psychological Medicine, 2018
15. Di Forti et al., The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study. Lancet Psychiatry, 2019.
16. Schreiner & Dunn, Residual Effects of Cannabis Use on Neurocognitive Performance After Prolonged Abstinence: A Meta-Analysis. Experimental and Clinical Psychopharmacology.
17. Schoeler et al., The effects of cannabis on memory function in users with and without a psychotic disorder: findings from a combined meta-analysis. Psychological Medicine, 2016.
18. Borque & Potvin, Cannabis and Cognitive Functioning: From Acute to Residual Effects, From Randomized Controlled Trials to Prospective Designs. Frontiers in Psychiatry, 2021.
19. Daedelow et al., Are psychotic-like experiences related to a discontinuation of cannabis consumption in young adults? Schizophrenia Research, 2021.
20. Power et al., Genetic predisposition to schizophrenia associated with increased use of cannabis. Molecular Psychiatry, 2014.
21. Schaefer et al., Adolescent Cannabis Use and Adult Psychoticism: A Longitudinal Co-Twin Control Analysis Using Data From Two Cohorts. Journal of Abnormal Psychology, 2021.
22. Loweke et al., Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia. Translational Psychiatry, 2012.
23. Köck et al, Cannabidiol Cigarettes as Adjunctive Treatment for Psychotic Disorders – A Randomized, Open-Label Pilot-Study. Frontiers in Psychiatry, 2021.
24. Ksir & Hart, Cannabis and Psychosis: a Critical Overview of the Relationship.
25. Large et al., Cannabis Use and Earlier Onset of Psychosis A Systematic Meta-analysis. Arch. Gen. Psychiatry, 2011.
26. Scott et al., Association of Cannabis With Cognitive Functioning in Adolescents and Young Adults: A Systematic Review and Meta-analysis. JAMA Psychiatry, 2018.
27. Meier et al, Long-Term Cannabis Use and Cognitive Reserves and Hippocampal Volume in Midlife. American Journal of Psychiatry, 2022.
28. Røgeberg O., Correlations between cannabis use and IQ change in the Dunedin cohort are consistent with confounding from socioeconomic status. PNAS, 2013.
29. Meier et al., Associations between Adolescent Cannabis Use and Neuropsychological Decline: A Longitudinal Co-Twin Control Study. Addiction, 2018.
30. Jackson et al., Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies. PNAS, 2016.
31. Kuc et al., Psychedelic experience dose‑dependently modulated by cannabis: results of a prospective online survey. Psychopharmacology, 2021.
32. Lukas & Orozco, Ethanol increases plasma D 9-tetrahydrocannabinol (THC) levels and subjective effects after marihuana smoking in human volunteers. Drug and Alcohol Dependence, 2001.
33. Hartman et al., Controlled Cannabis Vaporizer Administration: Blood and Plasma Cannabinoids with and without Alcohol. Clinical Chemistry, 2015.
34. Lukas et al., Marihuana attenuates the rise in plasma ethanol levels in human subjects. Neuropsychopharmacology, 1992.
35. Perez-Reyes & Cook, On the Marihuana Attenuation of the Rise of Ethanol Levels in Human Subjects. Neuropsychopharmacology, 1993.
36. Fisher et al., Lower-Risk Cannabis Use Guidelines (LRCUG) for reducing health harms from non-medical cannabis use: A comprehensive evidence and recommendations update. International Journal of Drug Policy, 2022.
37. De Sousa Fernandes Perna et al., Subjective aggression during alcohol and cannabis intoxication before and after aggression exposure. Psychopharmacology, 2016.
38. Myerscough, R. and S. Taylor, The effects of marijuana on human physical aggression. Journal of Pers Social Psychology, 1985.
39. Taylor, S.P., et al., The effects of alcohol and delta-9-tetrahydrocannabinol on human physical aggression. Aggressive Behavior, 1976.
40. Cherek, D.R., et al., Acute effects of marijuana smoking on aggressive, escape and point-maintained responding of male drug users. Psychopharmacology. 1993
41. Cherek, D.R. and D.M. Dougherty, Provocation frequency and its role in determining the effects of smoked marijuana on human aggressive responding. Behavioural Pharmacology, 1995.
42. Lehrer et al., Marijuana and Myocardial Infarction in the UK Biobank Cohort. Cureus, 2022.
43. Infante et al., Adolescent Brain Surface Area Pre- and Post-Cannabis and Alcohol Initiation. J Stud Alcohol Drugs, 2018.
44. Mahmood et al., Learning and Memory Performances in Adolescent Users of Alcohol and Marijuana: Interactive Effects. J stud Alcohol drugs, 2010.
45. Adejumo et al., Cannabis use is associated with reduced prevalence of progressive stages of alcoholic liver disease. Liver Int, 2018.
46. Acute memory and psychotomimetic effects of cannabis and tobacco both 'joint' and individually: a placebo-controlled trial
47. Impey et al., Mismatch negativity in tobacco-naïve cannabis users and its alteration with acute nicotine administration. Pharmacology, Biochemistry & Behavior, 2015.
48. The Effects of Nicotine and Cannabis Co-Use during Adolescence and Young Adulthood on White Matter Cerebral Blood Flow Estimates
49. Agrawal et al., Simultaneous cannabis and tobacco use and cannabis-related outcomes in young women. Drug and Alcohol Dependence, 2009.
50. Weed et al., Ventilatory-depressant effects of opioids alone and in combination with cannabinoids in rhesus monkeys. European Journal of Pharmacology, 2018.
51. Hattendorf et al., Interaction between delta(9)-tetrahydrocannabinol and d-amphetamine. Psychopharmacology, 1977.
52. Quigley & McCabe, The relationship between nicotine and psychosis. Therapeutic Advances in Psychopharmacology, 2019.
53. Chen et al., Brain cannabinoid receptor 2: expression, function and modulation. Acta Pharmacologica Sinica, 2017.
54. Murillo-Rodriguez et al., Cannabinoids and Neuropsychiatric Disorders. Advances in Experimental Medicine and Biology, 2019.
55. Huestis et al., Human Cannabinoid Pharmacokinetics. Chemistry & Biodiversity, 2007.
56. Verweij et al., A genetic perspective on the proposed inclusion of cannabis withdrawal in the DSM-5. Psychological Medicine, 2013.
57.Perisetti et al., Cannabis hyperemesis syndrome: an update on the pathophysiology and management. Annals of Gastroenterology, 2020.
58. Drennan et al., Acute objective and subjective intoxication effects of legal‑market high potency THC‑dominant versus CBD‑dominant cannabis concentrates. Nature Scientific Reports, 2021.
2. Zuurman et al., Biomarkers for the effects of cannabis and THC in healthy volunteers. British Journal of Clinical Pharmacology, 2008.
3. Hall et al., What is the prevalence and risk of cannabis use disorders among people who use cannabis? A systematic review and meta-analysis. Addictive Behaviors, 2020.
4. Mathew et al., Acute cannabis toxicity. Clinical toxicology, 2019.
5. Rigucci et al., Effects of high-potency cannabis on corpus callosum microstructure. Psychological Medicine, 2016.
6. Ravi et al., Associations Between Marijuana Use and Cardiovascular Risk Factors and Outcomes. Annals of Internal Medicine, 2018.
7. Johnson-Sasso et al., Marijuana use and short-term outcomes in patients hospitalized for acute myocardial infarction. PLoS ONE, 2018
8. Abuhasira et al., Cannabis is associated with blood pressure reduction in older adults – A 24-hours ambulatory blood pressure monitoring study. European Journal of Internal Medicine, 2021.
9. Hall, What has research over the past two decades revealed about the adverse health effects of recreational cannabis use? Addiction, 2015.
10. Freeman & Winstock, Examining the profile of high-potency cannabis and its association with severity of cannabis dependence. Psychological Medicine, 2015.
11. Wall et al., Dissociable effects of cannabis with and without cannabidiol on the human brain's resting-state functional connectivity. Journal of Psychopharmacology, 2019.
12. D'Souza et al., Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis. The World Journal of Biological Psychiatry, 2022.
13. Hjorthøi et al., Development Over Time of the Population-Attributable Risk Fraction for Cannabis Use Disorder in Schizophrenia in Denmark. JAMA Psychiatry, 2021.)
14. Sami et al., Psychotic-like experiences with cannabis use predict cannabis cessation and desire to quit: a cannabis discontinuation hypothesis. Psychological Medicine, 2018
15. Di Forti et al., The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study. Lancet Psychiatry, 2019.
16. Schreiner & Dunn, Residual Effects of Cannabis Use on Neurocognitive Performance After Prolonged Abstinence: A Meta-Analysis. Experimental and Clinical Psychopharmacology.
17. Schoeler et al., The effects of cannabis on memory function in users with and without a psychotic disorder: findings from a combined meta-analysis. Psychological Medicine, 2016.
18. Borque & Potvin, Cannabis and Cognitive Functioning: From Acute to Residual Effects, From Randomized Controlled Trials to Prospective Designs. Frontiers in Psychiatry, 2021.
19. Daedelow et al., Are psychotic-like experiences related to a discontinuation of cannabis consumption in young adults? Schizophrenia Research, 2021.
20. Power et al., Genetic predisposition to schizophrenia associated with increased use of cannabis. Molecular Psychiatry, 2014.
21. Schaefer et al., Adolescent Cannabis Use and Adult Psychoticism: A Longitudinal Co-Twin Control Analysis Using Data From Two Cohorts. Journal of Abnormal Psychology, 2021.
22. Loweke et al., Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia. Translational Psychiatry, 2012.
23. Köck et al, Cannabidiol Cigarettes as Adjunctive Treatment for Psychotic Disorders – A Randomized, Open-Label Pilot-Study. Frontiers in Psychiatry, 2021.
24. Ksir & Hart, Cannabis and Psychosis: a Critical Overview of the Relationship.
25. Large et al., Cannabis Use and Earlier Onset of Psychosis A Systematic Meta-analysis. Arch. Gen. Psychiatry, 2011.
26. Scott et al., Association of Cannabis With Cognitive Functioning in Adolescents and Young Adults: A Systematic Review and Meta-analysis. JAMA Psychiatry, 2018.
27. Meier et al, Long-Term Cannabis Use and Cognitive Reserves and Hippocampal Volume in Midlife. American Journal of Psychiatry, 2022.
28. Røgeberg O., Correlations between cannabis use and IQ change in the Dunedin cohort are consistent with confounding from socioeconomic status. PNAS, 2013.
29. Meier et al., Associations between Adolescent Cannabis Use and Neuropsychological Decline: A Longitudinal Co-Twin Control Study. Addiction, 2018.
30. Jackson et al., Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies. PNAS, 2016.
31. Kuc et al., Psychedelic experience dose‑dependently modulated by cannabis: results of a prospective online survey. Psychopharmacology, 2021.
32. Lukas & Orozco, Ethanol increases plasma D 9-tetrahydrocannabinol (THC) levels and subjective effects after marihuana smoking in human volunteers. Drug and Alcohol Dependence, 2001.
33. Hartman et al., Controlled Cannabis Vaporizer Administration: Blood and Plasma Cannabinoids with and without Alcohol. Clinical Chemistry, 2015.
34. Lukas et al., Marihuana attenuates the rise in plasma ethanol levels in human subjects. Neuropsychopharmacology, 1992.
35. Perez-Reyes & Cook, On the Marihuana Attenuation of the Rise of Ethanol Levels in Human Subjects. Neuropsychopharmacology, 1993.
36. Fisher et al., Lower-Risk Cannabis Use Guidelines (LRCUG) for reducing health harms from non-medical cannabis use: A comprehensive evidence and recommendations update. International Journal of Drug Policy, 2022.
37. De Sousa Fernandes Perna et al., Subjective aggression during alcohol and cannabis intoxication before and after aggression exposure. Psychopharmacology, 2016.
38. Myerscough, R. and S. Taylor, The effects of marijuana on human physical aggression. Journal of Pers Social Psychology, 1985.
39. Taylor, S.P., et al., The effects of alcohol and delta-9-tetrahydrocannabinol on human physical aggression. Aggressive Behavior, 1976.
40. Cherek, D.R., et al., Acute effects of marijuana smoking on aggressive, escape and point-maintained responding of male drug users. Psychopharmacology. 1993
41. Cherek, D.R. and D.M. Dougherty, Provocation frequency and its role in determining the effects of smoked marijuana on human aggressive responding. Behavioural Pharmacology, 1995.
42. Lehrer et al., Marijuana and Myocardial Infarction in the UK Biobank Cohort. Cureus, 2022.
43. Infante et al., Adolescent Brain Surface Area Pre- and Post-Cannabis and Alcohol Initiation. J Stud Alcohol Drugs, 2018.
44. Mahmood et al., Learning and Memory Performances in Adolescent Users of Alcohol and Marijuana: Interactive Effects. J stud Alcohol drugs, 2010.
45. Adejumo et al., Cannabis use is associated with reduced prevalence of progressive stages of alcoholic liver disease. Liver Int, 2018.
46. Acute memory and psychotomimetic effects of cannabis and tobacco both 'joint' and individually: a placebo-controlled trial
47. Impey et al., Mismatch negativity in tobacco-naïve cannabis users and its alteration with acute nicotine administration. Pharmacology, Biochemistry & Behavior, 2015.
48. The Effects of Nicotine and Cannabis Co-Use during Adolescence and Young Adulthood on White Matter Cerebral Blood Flow Estimates
49. Agrawal et al., Simultaneous cannabis and tobacco use and cannabis-related outcomes in young women. Drug and Alcohol Dependence, 2009.
50. Weed et al., Ventilatory-depressant effects of opioids alone and in combination with cannabinoids in rhesus monkeys. European Journal of Pharmacology, 2018.
51. Hattendorf et al., Interaction between delta(9)-tetrahydrocannabinol and d-amphetamine. Psychopharmacology, 1977.
52. Quigley & McCabe, The relationship between nicotine and psychosis. Therapeutic Advances in Psychopharmacology, 2019.
53. Chen et al., Brain cannabinoid receptor 2: expression, function and modulation. Acta Pharmacologica Sinica, 2017.
54. Murillo-Rodriguez et al., Cannabinoids and Neuropsychiatric Disorders. Advances in Experimental Medicine and Biology, 2019.
55. Huestis et al., Human Cannabinoid Pharmacokinetics. Chemistry & Biodiversity, 2007.
56. Verweij et al., A genetic perspective on the proposed inclusion of cannabis withdrawal in the DSM-5. Psychological Medicine, 2013.
57.Perisetti et al., Cannabis hyperemesis syndrome: an update on the pathophysiology and management. Annals of Gastroenterology, 2020.
58. Drennan et al., Acute objective and subjective intoxication effects of legal‑market high potency THC‑dominant versus CBD‑dominant cannabis concentrates. Nature Scientific Reports, 2021.
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