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Saturday, May 18, 2013

Marijuana (Cannabis) Use: A Summary of Recent Research

Marijuana is the most commonly smoked illegal substance in many countries (Underner at al, 2013). Recent research in France has shown that the public views marijuana as having the highest perceived benefit for users (Reynaud et al., 2013) despite its effect on brain structure and thinking abilities remaining controversial (Cunha et al., 2013).

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Smoking marijuana  has a known negative impact on breathing functions (e.g., more breathing symptoms and development of acute bronchitis) due to the increased time that the smoke stays in the lungs as a result of the inhalation technique differing from that of tobacco inhalation (Underne et al., 2013). Bronchitis is a type of common lung disease characterized by increased mucus in the windpipe and bronchi (small airways). While marijuana use rapidly dilates the bronchi, chronic marijuana irritates the bronchi, inflames the airway, increases airway resistance, and alters the activity of macrophages in the alveoli that normally get rid of bacteria and fungi (Underner at al, 2013). Macrophages are types of white blood cells that engulf and digest (eat) harmful substances in the body. The alveoli are balloon-like sacs in the lungs that air travels to.

People are known to use marijuana as a way to cope with negative emotions, are more likely to use it in social situations (especially if they see others using it) than when alone, and use more behavioral than cognitive strategies to quit using it (Buckner et al, 2013).

Marijuana is known to induce psychosis, in which a person loses touch with reality. However, in an interesting new study from Brazil, researchers found that patients who used marijuana with a first episode of psychosis had fewer structural brain abnormalities (better brain tissue preservation) and fewer problems with aspects of attention, concentration , and executive functioning (carrying out a speeded verbal searching strategy) compared to other psychotic patients who did not report a history of marijuana use (Ciunha et al., 2013, 2013).

In a process known as mulling, some people add tobacco to marijuana (technically cannabis resin) for its consumption, which results in significant nicotine exposure (Belanger et al., 2013). One cigarette containing tobacco and cannabis resin is more harmful than a cigarette only containing tobacco (Underner et al., 2013). Recent case study evidence shows that the anti-psychotic medication, Abilify, can completely stop such psychotic reactions after marijuana consumption but that it has no effect on smoking level (Rolland et al., 2013).

Evidence continues to emerge that marijuana is a gateway drug. For example, recreational Ecstasy use is partially predicted by early marijuana use although other factors were found to play a more important role such as knowing people who use Ecstasy or attendance at dance music events (Smirnov et al., 2013). Ecstasy is an illegal drug known for causing distinct social-emotional effects.  Research has also emerged showing that patients who ingest large quantities of seeds from the Convolvulaceae family (also known as bindweed or early morning glory) are frequently known to use marijuana (Juszczak and Swiergiel, 2013.  These seeds are known to have significant psychoactive effects when consumed in large quantities.

Some people abuse synthetic marijuana (known as synthetic cannabinoid) which is a designer drug created from natural herbs that imitates the effects of marijuana when consumed. A recent case study reported on a young man with schizophrenia (a type of psychotic disorder) who developed the first known case of severe and life-threatening catatonia rapidly after synthetic marijuana use that was successfully treated with ECT (electrconvulsive therapy) after a failed trial of benzodiazapines (a type of anti-anxiety medication) (Leibu et al., 2013). Catatonia is a condition characterized by a lack of movement, rigid muscles, and agitation. Electroconvulsive therapy is the process of causing convulsions (abnormal, severe, involuntary muscle movements) by passing controlled levels of electricity through the brain. In the aforementioned case study, non-adherence to anti-psychotic medication in addition to synthetic marijauana use was believed to cause the rapid onset of catatonia.

Recent research has shown that marijuana is one of the most commonly abuse substances among HIV-infected persons entering jail. In such individuals,  use of marijuana (and other drugs) is associated with not having an HIV provider, not being prescribed antiretroviral therapy (medications that treat HIV), and low levels of antiretroviral medication adherence if they were prescribed the medication (Chitsaz et al., 2013).

For these reasons and others, attempts to detect cannabis dependence is important in medical settings. This generally involves the use of self-report scales as a non-invasive screening tool. However, one such measure, the Severity of Dependence Scale, was not recommended for use as a screening instrument due to difficulties differentiating between those with a marijuana dependence versus non-dependence (van der Pol et al,  2013). When detected, clinicians are encouraged to offer patients support in quitting marijuana smoking to bring about important benefits in lung functioning (Underner at al., 2013) and other health benefits.


BĂ©langer RE, Marclay F, Berchtold A, Saugy M, Cornuz J, Suris JC. (2013). To What Extent Does Adding Tobacco to Cannabis Expose Young Users to Nicotine? Nicotine Tob Res. (Epub).

Buckner JD, Zvolensky MJ, Ecker AH. (2013). Cannabis use during a voluntary quit attempt: An analysis from ecological momentary assessment. Drug Alcohol Depend. Epub.

Chitsaz E, Meyer JP, Krishnan A, Springer SA, Marcus R, Zaller N, Jordan AO, Lincoln T, Flanigan TP, Porterfield J, Altice FL.(2013). Contribution of Substance Use Disorders on HIV Treatment Outcomes and Antiretroviral Medication Adherence Among HIV-Infected Persons Entering Jail. AIDS Behav. (Epub).

Cunha PJ, Rosa PG, Ayres AD, Duran FL, Santos LC, Scazufca M, Menezes PR, Dos Santos B, Murray RM, Crippa JA, Busatto GF, Schaufelberger MS. (2013). Cannabis use, cognition and brain structure in first-episode psychosis. Schizophr Res. (Epub).

Juszczak GR, Swiergiel AH. Recreational use of D-lysergamide from the seeds of Argyreia nervosa, Ipomoea tricolor, Ipomoea violacea, and Ipomoea purpurea in Poland.(2013). J Psychoactive Drugs. 45(1):79-93.

Leibu E, Garakani A, McGonigle DP, Liebman LS, Loh D, Bryson EO, Kellner CH. (2013). Electroconvulsive Therapy (ECT) for Catatonia in a Patient With Schizophrenia and Synthetic Cannabinoid Abuse: A Case Report. J ECT. (Epub).

Reynaud M, Luquiens A, Aubin HJ, Talon C, Bourgain C. (2013). Quantitative damage-benefit evaluation of drug effects: major discrepancies between the general population, users and experts. J Psychopharmacol. (Epub).

Rolland B, Geoffroy PA, Jardri R, Cottencin O. (2013). Aripiprazole for treating cannabis-induced psychotic symptoms in ultrahigh-risk individuals. Clin Neuropharmacol. 36(3):98-9.

Smirnov A, Najman JM, Hayatbakhsh R, Wells H, Legosz M, Kemp R. (2013). Young adults' recreational social environment as a predictor of Ecstasy use initiation: findings of a population-based prospective study. Addiction. 2013. (Epub).

Underner M, Urban T, Perriot J, Peiffer G, Meurice JC. (2013). Cannabis use and impairment of respiratory function. Rev Mal Respir. 30(4):272-85.

van der Pol P, Liebregts N, de Graaf R, Korf DJ, van den Brink W, van Laar M. (2013). Reliability and validity of the Severity of Dependence Scale for detecting cannabis dependence in frequent cannabis users. Int J Methods Psychiatr Res. (Epub).


  1. This comment has been removed by a blog administrator.

  2. I think it's important to read this article on cannabie with a pinch of salt. Even as a published paper, here tends to be a bit of a skew depending on the views of the person writing the article and I found that there obviously wasn't enough argument for the benefits of marijuana as opposed to the negative effects!

  3. Hi Sheila. This was not meant to be a comprehensive balanced review but just a review on some of the most recent publications on the topic and that is what they were at the time it was written.


Your comments are welcome.