What is right for you, is not necessarily right for others.

There are some genes that make people more prone to psychosis induced by Cannabis, not everyone are like this. Same with other stuff, LSD doesn't cause schizophrenia, but in some people it may trigger an underlaying schizophrenia.

I smoked weed for years, never was psychotic/manic/hypomanic as a result of this use. However, today I don't smoke weed because I simply don't know how it may affect my moods long-term.