Hypothesis: Schizotypal personality disorder patients will show cognitive improvements in 1) working memory 2) learning and memory 3) sustained attention 4) enhanced performance on the AX-CPT, N-back and Eriksen during pergolide treatment. There will be a significant diagnosis by drug administration of 0.3 mg of oral pergolide interaction for performance on the cognitive tasks, with the schizotypal personality disorder group demonstrating significantly improved peformance compared to the other personality disorder group after pergolide compared with placebo.