Currently, no study to date has directly tested a selective D1R agonist in relation to the cognitive impairment of Schizophrenia without the confound of neuroleptics. The investigators propose to examine the efficacy of DAR-0100A, a highly selective, full D1R agonist supported by pre-clinical and preliminary pilot clinical data, in ameliorating the cognitive deficits in Schizotypal Personality Disordered subjects receiving no medications including antipsychotics.