Psychiatr News February 3, 2006
Volume 41, Number 3, page 23
© 2006 American Psychiatric Association
Marijuana-Induced Psychosis May Foretell Future Episodes
Joan Arehart-Treichel
Few individuals who smoke marijuana experience psychosis afterward. However, when marijuana-related psychosis does occur, it may be a warning sign that more psychotic episodes could occur.
Reports from various researchers have suggested that marijuana-induced psychosis is generally short-lived and that total remission can be expected. Such reports, however, have been based on case studies, not on long-term follow-up data, according to the authors of a new, long-term study.
The study found that an episode of marijuana-induced psychosis is not innocuous—it often presages subsequent psychotic episodes and a diagnosis of a schizophrenia-spectrum disorder.
Mikkel Arendt, Ph.D., a fellow at the Center for Basic Psychiatric Research at the University of Aarhus in Denmark, and coworkers used the Danish Psychiatric Central Register to identify patients treated for a first marijuana-induced psychotic episode between 1994 and 1999. There were 535 such patients. The researchers then followed those patients for at least three years to determine how many of them experienced subsequent psychotic episodes and how many could be diagnosed with a schizophrenia-spectrum disorder.
The researchers found that 77 percent of the subjects incurred subsequent psychotic episodes and that 45 percent could be diagnosed at some time within the next three years or more with a schizophrenia-spectrum disorder. Moreover, of the 45 percent who developed a schizophrenia-spectrum disorder after experiencing marijuana-induced psychosis, 37 percent received such a diagnosis within three years and the remaining eight after three years. Furthermore, those who developed such a disorder did so at an earlier age than did comparison subjects—individuals who developed such a disorder but who had no recorded history of marijuana-induced psychotic symptoms. This effect was most marked for paranoid schizophrenia.
"An episode of short-lived psychotic symptoms following cannabis use seems to have great prognostic value."
Thus, "for the majority of patients, cannabis-induced psychotic symptoms proved to be a first step in the development of a schizophrenia-spectrum disorder or other severe psychopathology," Arendt and his group concluded in their study report, which was published in the December 2005 British Journal of Psychiatry.
Good luck man, especially if your interested in smoking for its medical value.
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![:\](https://bluelight.org/xf/BL_Images/Orig_Emoji/wrygrin.gif "wry grin :\")