It's kind of worse with alcohol because the psychosis associated with that as an exacerbating factor is more related to alcoholic encephalopathy, Wernicke-Korsakoff syndrome etc... much of which can be brought on with self medicating with alcohol. Definitely a component but more like psychosis and mania drive you to drink because these experiences are awful more than a causative factor that's been proven

https://www.ncbi.nlm.nih.gov/books/NBK459134/

The aldehydes that are produced from drinking alcohol heighten the risk for schizophrenia if you carry certain genetics.

https://pubmed.ncbi.nlm.nih.gov/26941382/

Interesting - we've known these are very bad for you for years but I had not heard of a direct link

Even peculiarly stressful life events can trigger onset

Complicated interaction.

Schizos may take alcohol or cigarettes to calm down, a form of self medication. On the long term these may worsen, in the immediate they help. Why do you think they smoke a lot?!? To treat. If you smoke or drink, what do you do after a tough day - smoke or drink, to relax, feels great. Schizos may have a tough day , but not from external stimuli, but from internal stimuli

Nicotine is a more effective schizophrenia treatment than the actual medications, which is why over 80% of them smoke.

https://pmc.ncbi.nlm.nih.gov/articles/PMC2613326/

That study might say that there is promise in further research instead of better, but yes a lot of smokers.

Alcohol is pretty bad for your brain so I would not be surprised. And while it's not really a hallucinogen itself (comparatively) I've heard some pretty hellish stories of severe alcohol withdrawals. Just going without sleep (completely) for several days can cause hallucinations and stress - and this is a common symptom of more serious withdrawal.

I would imagine other drugs which produce severe (and stressful) withdrawal could also trigger this. The stress alone cannot be good.

Nobody serious believe that alcohol is harmless. There are many anti-alcohol campaign and laws always running around. It's just that alcohol has been part of our culture for thousands of year, that we monstly manage it. It's not the case of cannabis, psilocybin and even less LSD (even if you can find historic usage for the not man made ones)