What happens if you have psychosis and you smoke cannabis? If you stop smoking cannabis, will your symptoms get better?

Professor Robin Murray: Patients often say: ‘well I take cannabis because it makes me feel better.’ Well if that is the case, then people who are psychotic and taking cannabis they ought to do better, because the cannabis is making them feel better. But we found after following up about 100 people, 4 years on the people who were still taking cannabis were doing much worse.

The evidence we have about stopping cannabis, and the outcome of psychosis is, it depends how long you’re smoking for. So for example, if this is one’s first episode of psychosis, and one perhaps has not smoked quite so much, smoked cannabis for 2 or 3 years, you can stop and you might have a good chance of, you take the antipsychotics for a while, you don’t take any more drugs, you might just very gradually get better over 2 or 3 years.

If, on the other hand, you have been battering at cannabis for 15 years, taking high-grade skunk, and you’ve had several episodes of psychosis, you can stop taking the cannabis, but by that time probably, the damage is done.  Probably things have happened in your brain, which will not revert to normal, sadly.