OBJECTIVES To assess the reasons for discontinuation and for continuation of antipsychotic medication in the treatment of schizophrenia from patient and clinician perspectives. METHODS Two measures were developed to assess the Reasons for Antipsychotic Discontinuation/Continuation (RAD), one from patient's perspective (RAD-I), and the other from clinician's perspective (RAD-Q). These measures were administered to patients enrolled in a 12-week study of antipsychotic medication in the treatment of schizophrenia (N=630). Reasons for discontinuation and reasons for continuation with the assigned antipsychotic during the study were assessed. Reported reasons were rated as being a primary reason, very important, somewhat important, or of minor importance. The top primary reasons for medication discontinuation and continuation were identified from patient and clinician perspectives, and level of concordance between patients' and clinicians' reasons was assessed. RESULTS The top primary reasons for medication discontinuation differed from the top primary reasons for continuation on the medication, with a high level of concordance between patients' and clinicians' perspectives. The top three primary reasons for medication discontinuation were insufficient improvement or worsening of positive symptoms, medication-related adverse events, and insufficient improvement or worsening of mood symptoms. The top three primary reasons for medication continuation were improvement in positive symptoms, subjective perception of improvement, and improvement in level of functioning. CONCLUSIONS Medication efficacy appears to be the core driver of medication continuation and discontinuation, especially with regard to positive symptoms. Reasons for medication discontinuation differ somewhat from reasons for continuation, with a high level of concordance between patients' and clinicians' perspectives.