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Cannabis, or marijuana, is a psychoactive herb that comes from the cannabis plant. This mind-altering substance is an illegal drug in most states; however, laws are changing, especially in the western regions. Marijuana is a mixture of dried, shredded flowers, as well as leaves of the plant Cannabis sativa. Stronger forms of cannabis include sinsemilla, hashish or hash, and hash oil.

Marijuana is usually smoked, and can be found in electronic cigarettes as well as in cigars that have been emptied of tobacco and refilled with marijuana, known as blunts. Marijuana cigarettes or blunts sometimes include crack cocaine, and some users mix marijuana in food or brew it in tea.

All forms of cannabis are mind-altering, psychoactive drugs, and all forms contain delta-9-tetrahydrocannabinol (THC), the main active chemical in marijuana. Marijuana's effect on the user depends on the amount of THC in which the person is exposed. The potency of the drug is measured by the average amount of THC in test samples confiscated by law enforcement agencies. These samples showed the following:

  • Most ordinary marijuana contained, on average, 7 percent THC.
  • Sinsemilla, from buds, contained 12 percent THC on average, but ranged from less than 1 percent to 27 percent.
  • Hashish, the sticky resin from female flowers, had an average of 10 percent THC, but ranged from 1 percent to 26 percent.

In addition, research that appeared in The Lancet Psychiatry has found that in people who smoke cannabis regularly, or those who smoke it with a high THC potency, are at more at risk for first psychotic episodes.

The Monitoring the Future Survey, conducted yearly, includes students from middle through high school. An important finding from a recent survey is the dramatic increase in vaping by adolescents. There has been a significant increase in the vaping of all three substances nicotine, marijuana, as well as flavoring alone. There has also been little change in marijuana use in this age bracket. Marijuana prevalence rose by .5 percent points to 23.9 percent in 2018, while there was a significant increase in the prior year. Annual prevalence stands at 11 percent, 28 percent, and 36 percent in grades 8, 10, and 12 respectively.


Sign and symptoms as cataloged by the DSM-5:

A problematic pattern of cannabis use leading to clinically significant impairment or dis­tress, as manifested by at least two of the following, occurring within a 12-month period:

  • Cannabis is often taken in larger amounts or over a longer period than intended.
  • There is a persistent desire or unsuccessful efforts to cut down or control cannabis use.
  • A great deal of time is spent in activities necessary to obtain cannabis, use canna­bis, or recover from its effects.
  • Craving or a strong desire or urge to use cannabis.
  • Recurrent cannabis use resulting in a failure to fulfill major obligations at work, school, or home.
  • Continued cannabis use despite having persistent or recurrent social or interper­sonal problems caused or exacerbated by the effects of cannabis.
  • Important social, occupational, or recreational activities are given up or reduced be­cause of cannabis use.
  • Recurrent cannabis use in situations in which it is physically hazardous.
  • Cannabis use is continued despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by cannabis.

Tolerance, as defined by either of the following:

  • A need for markedly increased amounts of cannabis to achieve intoxication or desired effect.
  • Markedly diminished effect with continued use of the same amount of cannabis.
  • Withdrawal, as manifested by either of the following: The characteristic withdrawal syndrome for cannabis; cannabis is taken to relieve or avoid withdrawal symptoms.

Because some cannabis users are motivated to minimize their amount or frequency of use, it is important to be aware of common signs and symptoms of cannabis use and intox­ication so as to better assess the extent of use. As with other substances, experienced users of cannabis develop behavioral and pharmacological tolerance such that it can be difficult to detect when they are under the influence. Signs of acute and chronic use include red eyes (conjunctival injection), cannabis odor on clothing, yellowing of finger tips (from smoking joints), chronic cough, burning of incense (to hide the odor), and exaggerated craving and impulse for specific foods, sometimes at unusual times of the day or night.

With adolescent users, changes in mood stability, energy level, and eating patterns are commonly observed. These signs and symptoms are likely due to the direct effects of can­nabis use (intoxication) and the subsequent effects following acute intoxication (coming down), as well as attempts to conceal use from others. School-related problems are com­monly associated with cannabis use disorder in adolescents, particularly a dramatic drop in grades, truancy, and reduced interest in general school activities and outcomes.

Cannabis use disorder among adults typically involves well-established patterns of daily cannabis use that continue despite clear mental health or medical problems. Many adults have experienced repeated desire to stop or have failed at repeated cessation attempts. Milder adult cases may resemble the more common adolescent cases in that cannabis use is not as frequent or heavy but continues despite potential significant consequences of sustained use. Meanwhile, the rate of use among middle-age and older adults appears to be increasing.

Early onset of cannabis use (prior to age 15 years) is a robust predictor of the de­velopment of cannabis use disorder and other types of substance use disorders and mental disorders during young adulthood. Such early onset is likely related to concurrent other externalizing problems, most notably conduct disorder symptoms. However, early onset is also a predictor of internalizing problems and probably reflects a general risk factor for the development of mental health disorders.

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Associated features, development, and course as cataloged by the DSM-5:
Individuals who regularly use cannabis often report that it is being used to cope with mood, sleep, pain, or other physiological or mental health problems, and those diagnosed with cannabis use disorder frequently do have other concurrent mental disorders. Careful assessment typically reveals reports of cannabis use contributing to exacerbation of these same symptoms, as well as other reasons for frequent use (to experience euphoria, to forget about problems, in response to anger, as an enjoyable social activity). Related to this issue, some individuals who use cannabis multiple times per day for the aforementioned reasons do not perceive themselves as (and thus do not report) spending an excessive amount of time under the influence or recovering from the effects of cannabis, despite be­ing intoxicated on cannabis or coming down from it effects for the majority of most days. An important marker of a substance use disorder diagnosis, particularly in milder cases, is continued use despite a clear risk of negative consequences to other valued activities or relationships (school, work, sport activity, partner or parent relationship).

The onset of cannabis use disorder can occur at any time during or following adolescence, but onset is most commonly during adolescence or young adulthood. Although much less frequent, onset of cannabis use disorder in the preteen years or in the late 20s or older can occur. Recent acceptance by some of the use and availability of "medical marijuana" may increase the rate of onset of cannabis use disorder among older adults.

Generally, cannabis use disorder develops over an extended period of time, although the progression appears to be more rapid in adolescents, particularly those with pervasive conduct problems. Most people who develop a cannabis use disorder typically establish a pattern of cannabis use that gradually increases in both frequency and amount. Cannabis, along with tobacco and alcohol, is traditionally the first substance that adolescents try. Many perceive cannabis use as less harmful than alcohol or tobacco use, and this percep­tion likely contributes to increased use. Moreover, cannabis intoxication does not typically result in as severe behavioral and cognitive dysfunction as does significant alcohol intox­ication, which may increase the probability of more frequent use in more diverse situa­tions than with alcohol. These factors likely contribute to the potential rapid transition from cannabis use to cannabis use disorder among some adolescents and the common pattern of using throughout the day that is commonly observed among those with more severe problems.

Cannabis use disorder among preteens, adolescents, and young adults is typically ex­pressed as excessive use with peers that is a component of a pattern of other delinquent behaviors usually associated with conduct problems. Milder cases primarily reflect continued use despite clear problems related to disapproval of use by other peers, school ad­ministration, or family, which also places the youth at risk for physical or behavioral consequences. In more severe cases, there is a progression to using alone or using through­out the day such that use interferes with daily functioning and takes the place of previ­ously established, prosocial activities.


Each individual is different, and treatment is tailored to a person's needs. First, individuals need to acknowledge whether they have a problem, which will make controlling their cravings easier. People in treatment can learn behavioral strategies to change habits. Sometimes, medications are part of the treatment regimen.

  • Treatment should enable patients to reduce drug use.
  • Improve the person's ability to function.
  • Minimize complications for people with additional medical problems such as heart disease or others.
  • Adopt healthier lifestyles.

Treatments for marijuana dependence can include:

  • Detoxification
  • Behavioral therapies
  • Counseling
  • Support groups

There are currently no medications for treating marijuana dependence. Drug treatment researchers are identifying which characteristics of users are predictors of treatment success and which approaches to treatment can be most helpful.

Find a Treatment Program here.

American Psychiatric Association—Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition
National Institute on Drug Abuse, Child Abuse and Neglect (NIDA)
National Institute on Drug Abuse
National Institutes of Health - U.S. National Library of Medicine
Monitoring the Future Survey
Last updated: 02/22/2019