Response to clozapine of rapid cycling versus non-cycling patients with a history of mania

Objective: Rapid cycling (RC) bipolar disorder (BD) patients often do not respond fully to mood-stabilizers. Atypical antipsychotics including clozapine may be good candidates as an alternative mood-stabilizer for these patients. Methods: Twenty-eight treatment-resistant patients with either Bipolar Disorder Type I (n = 20), or Schizoaffective Disorder Bipolar Type (n = 8) received clozapine add-on therapy. Patients were followed for up to 1 year. Patients were seen monthly and assessed on a number of symptom domains. Results: Fifteen of 28 patients met RC criteria. Differences between groups was non-significant for reported age of onset, age at study entry, past history of treatment or hospitalization, or diagnosis. However, significantly more women were RC. More than 80% of patients in either group showed at least some improvement over the 1-year study. Random regression analyses found the non-rapid cycling (NRC) group experienced significantly greater improvement than RC patients (p < 0.0001). Conclusions: Clozapine is more effective in NRC patients with a history of mania in comparison to patients with a recent history of RC.