Maybe, maybe not. “I would not want to tell my patients that it was one joint, for example, that caused their psychotic illness,” says Dr. Birnbaum. “I work with young folks who have been smoking heavily for the past several years, and I still wouldn’t confidently say that the pot caused schizophrenia. That’s just a dangerous thing to say.”
Developing a psychotic illness is multifactorial, says Dr. Birnbaum. “It’s never just one thing.”
On the other hand, both heavy use and an increase in use from occasional to daily — as well as earlier and longer exposure to pot — have been linked to psychosis. “Evidence suggests that pot smoking can lead to earlier onset — that it can develop it sooner than it would have otherwise,” says Dr. Birnbaum. “In addition, pot is also associated with development of illness in otherwise healthy individuals, meaning it is possible that psychosis would not have developed in that person if they had never smoked pot.”
But that, he says is “ hard to prove for sure and we don’t have a specific number of joints, a specific dose of cannabis, that we know is likely going to trigger a psychotic experience.”
Dr. Birnbaum gets this question from his patients a lot: if I’d never smoked pot, would this have still happened to me? And, he says it’s a question that’s virtually impossible to answer.