Copied from another reply:

Schizophrenia is a mental health disorder that can be triggered by psychoactive substances, trauma, or other significant events/life changes. Not everyone who has schizophrenia was guaranteed to get it, it’s just that some people have the potential for it. A psychotic episode (whether substance-induced or organic) is a common trigger to cause schizophrenia in someone that had the potential to develop the disorder.

If you have a family history of mental illnesses (particularly Schizophrenia and Bipolar disorder), significant THC use and substance-induced psychotic episodes can be the grain that tips the scale towards developing the disorder that may have otherwise been avoided.

(TL;DR: if Schizophrenia runs in your family, be exceedingly careful about what psychoactive substances you use.)