[jwdunne]

A personal anecdote of mine. A friend has schizophrenia. There was a clear point of descent from smoking cannabis. He was 13 at the time - young for schizophrenia. He's now on clozapine, a powerful antipsychotic. Whenever his judgement fails him and he smokes pot, it's weeks to months before he has to spend some time in hospital. Otherwise, he could take other, heavier drugs to excess and not require urgent hospitalisation.

The rule for him was always "cannabis triggers".

[jhayward]

You've illustrated the problem in anecdata: Nothing in what you said indicates that cannabis causes his episodes.

It is just as likely, given the description, that the sequence that results in an episode includes the prompts that trigger him to medicate with cannabis.

This is why we can't use personal experience to make public policy.

[jwdunne]

Nope. I understand that. I wouldn't say that cannabis causes schizophrenia or even episodes. It's more a story of how my friend and the people that love him came to view cannabis as it relates to his illness. It's an "understanding" if you will held by carers and primary care givers alike. If you suffer from psychosis, they make a point of warning about cannabis.

Perhaps the lapse in judgement is a sign of an oncoming episode, with weed unnecessarily blamed. But the experience of so many people and the possibility of a link deserves to be investigated with the rigour of science.

[mike10010100]

This exactly. Right now we have correlation. A ton of people in this thread are trying to divine causation.