1. The present study was designed to determine the impact of neuroleptic side effects on clinical outcome in generalized anxiety disorder.2. 205 outpatients entered the study. In an open label design fluspirilene 1.5mg per week was administered for a period of 6 weeks.3. Consistent with previous studies fluspirilene demonstrated again anxiolytic properties and was in general tolerated well.4. However, in responders significantly less side effects were observed than in nonresponders. The interaction between tolerability and clinical outcome is the main finding of the present study.5. In conclusion, the data suggest, that neuroleptic treatment of generalized anxiety disorder should be guided by paying more attention to potential side effects. If under neuroleptic treatment of generalized anxiety disorders side effects are observed, pharmacotherapy should be discontinued, because this fact predicts an unfavourable clinical outcome.