I've heard that cannabis exposure during teenage years increases the probability of developing schizophrenia-like symptoms later in life. What evidence is there that this is causal and not correlational?

Current references I'm reading and will try to form into an answer:

  • $\begingroup$ A couple of things: 1) Psychotic patients make more use of cannabis than non-psychotic patients 2) people who consume cannabis between 15-18 are more likely to display psychotic symptoms at 26 3) relevant paper: ncbi.nlm.nih.gov/pmc/articles/PMC2864503 $\endgroup$
    – Ebbinghaus
    Jun 27, 2017 at 9:42
  • $\begingroup$ 1. your best bet would be twin studies (concordance rate between MZ and DZ twins with/without cannabis exposure. 2. since i last checked, there is at least one study with evidence that cannabis has anti-psychotic properties in a group of treatment refractory individuals with schizophrenia. 3. you should clarify your term "schizophrenia-like" -- do you also consider schizotypy to fit this criterion. $\endgroup$
    – faustus
    Jul 10, 2017 at 17:18

1 Answer 1


I discovered a study relating to a longitudinal study of a cohort of 45 570 Swedish conscripts covering a 15 year difference in between the first testing of and after. They covered the Swedish conscripts who had taken cannabis ( Who used cannabis on more than '50 occasions' ) and the others who haven't and came to the conclusion that the subjects that taken cannabis had a higher likelihood of developing schizophrenic symptoms than their counterparts. In their own words,

"Persistence of the association after allowance for other psychiatric illness and social background indicated that cannabis is an independent risk factor for schizophrenia"

The study is here: https://www.sciencedirect.com/science/article/abs/pii/S0140673687926201


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.