You don't have to take it forever but the current guidelines are at least 6 months symptom free follow by a long taper off the drug(about 4-6 months) The tapering period must also be a relatively stress free period. I had one episode and I ended up on the meds for 2.5 years because the first time we tried to taper at a year I started having weird symptoms like anxiety and anger. Because of the changes to receptors in your brain its critical to taper off of these drugs---we were cutting aboout 1/4 of my initial dose every 6 weeks but I was on the lowest dose effective for psychosis so it may take longer on a higher dose. I've been off for 3 or 4 months now no relapse but your chances of relapse are increased for the first year.