My husband was on it for over four years. It can have severe side effects, so needs to be carefully monitored, but my husband was on 1.5mg per day, and thankfully he suffered no side effects. Before being prescribed risperidone, he had been suffering extreme paranoia, hallucinations & delusions, was very agitated and anxious and getting aggressive. I was spending hours every day just driving him around, trying to keep his mind off what he was hearing & seeing, and what he believed was going on. He wasn't sleeping, because he was terrified of what would happen. Once on the risperidone (with trazodone and exelon patches), he was calm, content and relaxed.