It is of interest to investigate the benefit of quetiapine treatment in these types of patients. Quetiapine possibly gives less side-effects because of the expected lack of elevated prolactin levels, which is of importance in this patient group, overrepresented by young females. In this double blind, randomized, placebo controlled, 8 week, parallel group, multi-center study, quetiapine (in flexible doses between 200 mg/day and 600 mg/day) will be compared with the placebo.