Cannabis can contribute to psychosis in some people, but for others it can calm them. Its interesting cannabis has not made me psychotic but I did experience that effect from Prozac.

But yeah I don't really know how it effects you individually but if you feel it's doing more harm than good quitting may be a good idea. I personally feel like I'd be worse off without it, but different things work for different people I suppose. I am not an expert though that's just my opinion based on information I've looked into and experienced.