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.