It's an antihistamine actually. And sometimes it's used for nausea. My son's pediatric pdoc uses it rather than benzos with kids because it is gentler and not addictive like benzos. Doesn't seem like it would be a med to cause psychosis, but who knows?

I did a quick search about psychosis as a side effect. I found plenty on it being prescribed to prevent psychosis and only one stat about it causing psychosis and the incidence was like .01% of several thousand side effect complaints. Doesn't sound like it is a common side effect at all.