"Reefer Madness" is inconclusive [1] (so far as agitating an underlying psychosis). Many proponents would regard this as a affirmative result, however it does go both ways.

> Is there proof that they have a tendency of triggering "latent" conditions, instead of generating the conditions?

Personally, I've had panic attacks (originating from paranoia) bought on by historical heavy use - the correlation isn't subtle at all. Did my paranoia drive me to the initial peace associated with the drug? I'd have a hard time arguing otherwise - it really, really helped at first. My life was altered positively days after the previous dosage. If I take it now the situation becomes unbearable in less than 5 seconds. Anecdote disclaimer, as well as not being the same psychoactive drug (but it is psychoactive).

[1]: https://jamanetwork.com/journals/jamapsychiatry/fullarticle/...