I work with someone who has had psychosis in the past and takes anti psychotic medication to manage this. He was, like your coworker, open with me about it. Like you I have no personal experience of psychosis and it’s understandable you’ve got concerns, I got a bit of a jolt when he started talking about it, however all I can say is this coworker of mine has never shown any danger at all to me or anyone. He’s just a person who happens to have psychosis and takes medication for it. I’m glad he feels he can talk openly about it, as with your coworker it may indicate trust that the person (you) confided in will handle that information appropriately.

My coworker is not my favourite coworker (for reasons other than mental illness related) but I have respect for how he’s managing his mental health and working a demanding job. My experience has taught me there’s nothing to fear.