Brand name

  • Cannabis
  • Cannabinoids
  • Cannabidiols
  • Cannabinols
  • THC

Epidemiology of marijuana use

  • According to the 2014 estimates from the United States National Survey on Drug Use and Health (NSDUH) 35 million persons aged 12 or older (13.2%) used cannabis in the past year.
  • These numbers were increased by 9.7 millions (2.6%) since 2004.
  • 15% or 1 in 7 of marijuana users were found to meet criteria for Cannabis Use Disorder.
  • Between 2004 and 2011, the emergency department visit rate increased from 51 to 73 visits per 100,000 population aged 12 or older, for cannabis-only use. Adolescents aged 12-17 years showed the largest increase in the cannabis-only involved emergency visit rate.



  • Nabilon (Cesamet)


THC Plasma concentrations decrease rapidly after the end of smoking due to rapid distribution into tissues and metabolism in the liver. THC is highly lipophilic and initially taken up by tissues that are highly perfused, such as the lung, heart, brain, and liver. This requires an individual to smoke one joint every 2 hours to achieve constant pleasure effect from marijuana. Because of high lipid solubility of cannabinoids, urine drug screen detects positive for days up to 4 weeks after last use of marijuana among daily smokers.


  • MJ makes you feel great-until it doesn’t. Short term positive effects are euphoria and enhanced perception. Not always so positive are: time distortion, hallucinations, anxiety (especially in patients with anxiety disorders), tachycardia, sleepiness, and impaired memory and problem solving.
  • MJ has negative long term effects on chronic users, especially those who started in their teens. These include amotivational syndrome, less success than peers in school and career pursuits, and possibly a reduction in IQ points.
  • MJ and psychosis are clearly associated. Smoking heavily can uncover a psychotic disorder earlier than it would have emerged otherwise. Whether it actually causes psychosis is more controversial.
  • Don’t smoke and drive. While high-driving is usually less hazardous than drunk-driving, MJ interferes with judgment and perceptions, leading to potential fatalities as well as arrests for DUIs. The highest risk period is during the hour immediately after getting high.
  • Withdrawal from regular MJ use does occur. A typical MJ detox in a heavy user will last 3 to 5 days and may include irritability, insomnia, anxiety, headache, nausea and vomiting, and sometimes diarrhea. Patients should drink plenty of fluids and plan to be out of commission for a while. You can provide anti-emetics and analgesics to smooth out the process.
  • We have no medications for treating marijuana use disorder. Dronabinol (Marinol) is a synthetic form of THC that is FDA approved for intractable nausea and AIDS wasting syndrome, but clinical trials have not shown it to be effective for substitution treatment of MJ abuse.

Drug Interactions

Cocaine and amphetamines may lead to increased hypertension, tachycardia and possible cardiotoxicity. Benzodiazepines, barbiturates, ethanol, opioids, antihistamines, muscle relaxants and other CNS depressants increase drowsiness and CNS depression. When taken concurrently with alcohol, marijuana is more likely to be a traffic safety risk factor than when consumed alone.

Adverse Effects

Psychological effects of marijuana use include disorientation, altered time and space perception, lack of concentration, impaired learning and memory, alterations in thought formation and expression, drowsiness, sedation, mood changes such as panic reactions and paranoia, and a more vivid sense of taste, sight, smell, and hearing. Stronger doses intensify reactions and may cause fluctuating emotions, flights of fragmentary thoughts with disturbed associations, a dulling of attention despite an illusion of heightened insight, image distortion, and psychosis. The most common physiological effects include increased heart rate, reddening of the eyes, dry mouth and throat, increased appetite, and vasodilatation.

The short term effects of marijuana use include problems with memory and learning, distorted perception, difficultly in thinking and problem-solving, and loss of coordination. Heavy users may have increased difficulty sustaining attention, shifting attention to meet the demands of changes in the environment, and in registering, processing and using information. In general, laboratory performance studies indicate that sensory functions are not highly impaired, but perceptual functions are significantly affected. The ability to concentrate and maintain attention are decreased during marijuana use, and impairment of hand-eye coordination is dose-related over a wide range of dosages. Impairment in retention time and tracking, subjective sleepiness, distortion of time and distance, vigilance, and loss of coordination in divided attention tasks have been reported. Note however, that subjects can often “pull themselves together” to concentrate on simple tasks for brief periods of time. Significant performance impairments are usually observed for at least 1-2 hours following marijuana use, and residual effects have been reported up to 24 hours.

Similar to any substance, cannabinoids produce some side effects. Side effects of cannabinoids include fatigue, paranoia, possible psychosis, memory problems, depersonalization, mood alterations, urinary retention, constipation, decreased motor coordination, lethargy, slurred speech, and dizziness. Impaired health including lung damage, behavioral changes, and reproductive, cardiovascular and immunological effects have been associated with regular marijuana use. Regular and chronic marijuana smokers may have many of the same respiratory problems that tobacco smokers have (daily cough and phlegm, symptoms of chronic bronchitis), as the amount of tar inhaled and the level of carbon monoxide absorbed by marijuana smokers is 3 to 5 times greater than among tobacco smokers. Smoking marijuana while shooting up cocaine has the potential to cause severe increases in heart rate and blood pressure.

Effects from smoking cannabis products are felt within minutes and reach their peak in 10-30 minutes. Typical marijuana smokers experience a high that lasts approximately 2 hours. Most behavioral and physiological effects return to baseline levels within 3-5 hours after drug use, although some investigators have demonstrated residual effects in specific behaviors up to 24 hours, such as complex divided attention tasks. Psychomotor impairment can persist after the perceived high has dissipated. In long term users, even after periods of abstinence, selective attention (ability to filter out irrelevant information) has been shown to be adversely affected with increasing duration of use, and speed of information processing has been shown to be impaired with increasing frequency of use.


This document is prepared by the “Mental Health for All” team. This document is provided for information purposes only and does not necessarily represent endorsement by or an official position of the Essentials of Medicine. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient’s medical history.


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