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Is there such a condition as cannabis-induced psychosis?

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Q. My 18 year old son has had a psychotic breakdown. I have noticed that he was depressed since the last 3 months, but reasoned it was because all his friends had left the country for university abroad, and he was the only one left behind and missed them. He stopped keeping in touch with them and lost interest in his studies. The psychiatrist says most likely the cause is cannabis psychosis, which he said is rare and happens to about 1 in a 100,000 people. I am aware that my son has tried cannabis and smoked regularly every weekend in his last semester of school. Thereafter, he smoked perhaps once or twice a month with his friends but since January this year, has not smoked at all. However, after a gap of 4 months he recently smoked one joint with a friend. This was his first and only smoke in 4 months. Within 3-4 days of this, he had a total breakdown.

While his thoughts are confused and he talks of every thought and word as having a dual “other” thought/word in his mind, he is otherwise very much aware that there is something wrong with him and that his strange thoughts are not reality. He feels a constant need to explain his thoughts. When talking of other things, he is however very clear and logical, replying to questions reasonably, and is even able to laugh at himself and his condition. However, the day is full of ups and downs for him. At times he is simply depressed, at others he is extremely agitated and wants to desperately stop the thoughts in his head. He sometimes smells odors, and hears voices, but at no time does he believe these smells/voices are real, and in fact is eager to tell me that his illness is making him hear these voices and distorting his thoughts. He also complains of pain in the head, seeing white flashes, and imagining buildings are moving. He is on Flupentixol (3 mg at night) and Olanzapine (2.5mg thrice a day).

His psychiatrist believes his condition is unlikely to be schizophrenia (my mother was schizophrenic), and he also believes that my son would eventually be okay with medication and therapy. Is my son’s condition likely to be cannabis induced psychosis? And what are the chances of him becoming totally okay once again?

Is there such a condition as cannabis-induced psychosis?

Answered by on -


This is a difficult question to answer. There are several possibilities that I can think of. But please know that I cannot know any of these for sure. There is the possibility, generally speaking, of drug induced psychosis. In fact, the theory states that drugs, even cannabis, which is considered a hallucinogenic and therefore a very dangerous drug, can cause psychotic illnesses or psychotic episodes. Since there is no known definitive cause of schizophrenia or other psychotic based disorders, drugs cannot be ruled out as a cause of these illnesses.

You also mentioned that your mother had schizophrenia. This tells me that your son, or others related to your mother in some manner, may have a predisposition to suffering from schizophrenia or psychotic based illnesses. Those who are predisposed to disorders such as these often need only a trigger to set these diseases in motion, and drugs, in this case, may have been that trigger. Drugs may have been enough to cause your son’s current illness symptoms. There are also individuals who suffer one psychotic episode and never another. To answer your question specifically, it is possible that your son will only have this one episode and never another. There also exists the possibility this one episode is the beginning of a serious mental illness and he will have re-occurring episodes of psychosis. It is difficult, if not impossible, to predict either of these scenarios with any certainty.

My advice to you is for you and your son to work with the psychiatrist to find medication and therapy that your son can tolerate and that he willing to participate in. With the right treatments, medication especially, it may be possible to prevent future psychotic episodes, regardless of his actual diagnosis. Make it your goal to find a good doctor and a good mental health team to work with. One last thing, please do what you can to prevent your son from using drugs. Continued drug use will only increase his chances of having future episodes. I hope this helps to answer your question. I wish you and your son the best of luck.

Is there such a condition as cannabis-induced psychosis?

Kristina Randle, Ph.D., LCSW

Kristina Randle, Ph.D., LCSW is a licensed psychotherapist and Assistant Professor of Social Work and Forensics with extensive experience in the field of mental health. She works in private practice with adults, adolescents and families. Kristina has worked in a large array of settings including community mental health, college counseling and university research centers.

APA Reference
Randle, K. (2018). Is there such a condition as cannabis-induced psychosis?. Psych Central. Retrieved on May 20, 2019, from
Scientifically Reviewed
Last updated: 8 May 2018
Last reviewed: By a member of our scientific advisory board on 8 May 2018
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