Why does benadryl (diphenhydramine) alleviate symptoms of bipolar, borderline, autism, & schizophrenia? i only feel normal & able to think clearly when i've taken some.

Anti-cholinergic: Hard to say why, but it's not impossible. It's known to act on the CNS andyour experience is yours to know. Here's some info that might help: https://en.wikipedia.org/wiki/Diphenhydramine Both the conditions you name and the chemistry are very complex. Don't over-use it, but as directed I'd guess it's safer than many other drugs that may not help as much as you say it does. Best!