Schizophrenia Daily News Blog

New Cannabis/Schizophrenia Evidence

More Evidence of Marijuana-induced Psychosis Discovered

Participants in a Swiss study who were taking cannabis-based drugs as part of a controlled therapeutic study have been found to experienced psychotic effects very similar to those experienced by people who had smoked cannabis (Marijuana).

These findings, which were not expected in such a controlled environment, were published in the peer-reviewed, open-access journal BMC Psychiatry.

    Dr. Bernard Favrat and colleagues, from the Institut Universitaire de Medecine Legale in Switzerland, were conducting a clinical trial into the effects of orally administered delta-9-tetrahydrocannibol (THC), the active ingredient in cannabis, when two of the male study participants began to experience degraded psychomotor functions and severe anxiety that is common of cannabis-induced psychosis. Other effects included transient symptoms of derealization and depersonalization, and paranoid delusions.
They were described by one subject as worse than those experienced after smoking cannabis. One subject was given dronabinol, a synthetic THC that has been in medical use in the USA since 1985. The other subject was asked to drink a decoction of natural THC. The authors hypothesise that the effect may have been because the THC had been ingested, rather than inhaled; digesting THC may produce potent THC metabolites, which induce psychotic effects.

Research such as this, into designing THC-based drugs has grown quickly in the last few years, because of the many therapeutic effects that have been linked with THC. In theory, these drugs might be used to minimize muscle spasticity in multiple sclerosis patients, to improve appetite in AIDS patients and alleviate pain in cancer patients undergoing chemotherapy.

In conclusion, the researchers state "While the oral route of administration achieves only limited blood concentrations, significant psychotic reactions may occur". The sample size in this study was very small and so it seems likely that it may be performed again - though ethics boards are increasingly likely try to avoid such studies given the substantial (and growing) body of research linking cannabis use and psychosis.

This new paper adds to the growing research evidence that cannabis might be more harmful than previously thought - especially with regard to its ties to psychosis and schizophrenia (in particular).

See the full paper at: Favrat B, Menetrey A, Augsburger M, et al., Two cases of "cannabis acute psychosis" following the administration of oral cannabis. BMC Psychiatry, 2005;5:17.

For more information on Cannabis and schizophrenia

Favrat and colleagues' report adds to the body of evidence that cannabis might be more harmful than previously thought. In the UK, cannabis was downgraded to class C early last year, but government officials have called for a review of the decision following a series of studies revealing that cannabis dramatically increases the risk of developing mental illnesses.