Interesting theory. A close friend's brother who was a marijuana user developed schizophrenia at around age 28 or 30. It's a horrible, horrible disease.
It’s not a theory— it is a published research trial in the British Medical Journal and cited by The Lancet.
Triggering of certain ID’d gene sequences posessed by people who react to THC-— with response as noted. And it alters the genes. This is not— 1920’s scare movies about marijuana. Chemistry has come much further. Such that pure— CBD, cannabidiol is a potential wonder drug (no THC in it pure) obviating the need for opiods. Hence Big Pharma not wanting to make it— and they COULD!