Validation of a clinician questionnaire to assess reasons for antipsychotic discontinuation and continuation among patients with schizophrenia.

The Reasons for Antipsychotic Discontinuation Questionnaire (RAD-Q) was designed to assess clinicians' perceptions of reasons for antipsychotic discontinuation or continuation. The current study examined psychometric properties of this instrument and patterns of antipsychotic discontinuation. The sample of 121 patients (81 discontinuation, 40 continuation) with schizophrenia or schizoaffective disorder was 66.9% male, with a mean age of 41.6 years. Treating clinicians reported a mean of 4.1 reasons for discontinuation and 7.5 reasons for continuation. RAD-Q domain scores were derived to quantify the impact of three factors on the decision to discontinue or continue: treatment benefits, adverse events, and distal reasons other than direct effects of the medication. Analysis of inter-rater reliability indicated an acceptable degree of agreement between clinicians (weighted Kappa for discontinuation scores=0.70-0.78). Correlations with symptom measures (Clinical Global Impression-Schizophrenia Scale (CGI-SCH), Positive and Negative Syndrome Scale (PANSS)) supported convergent validity of the benefits domain score (r=0.28-0.47; all p<0.05). Domain scores discriminated among groups of patients differing in clinician and patient-reported clinical variables. Results suggest that the RAD-Q is a useful detailed measure of reasons for antipsychotic discontinuation and continuation. Findings indicate that clinicians usually report multiple reasons for discontinuation, rather than a single reason for each patient.