I'm on Invega Sustenna and it works great, I'm also on Zyprexa but might be coming off that soon because I really don't think I need it. Anyway, I tried to stop taking a particular psych med by myself a few months ago and ended up having seizures, you should be fine if it's done under a doctor's supervision though.

As for the lack of motivation, I've heard good things about Wellbutrin for that.