Yes, research suggests a genetic predisposition, with the odds increasing (to about 10%) if schizophrenia is already present in the family. It is not cast in stone though - i.e. it is not 100% guaranteed that you would have it.

However, under the circumstances, I would avoid these substances as they could trigger an episode. Especially considering there is already susceptibility (i.e. genetic predisposition). No need to add further risk factors..

Good mental health and habits would serve you best..