Background:
Little is known about the specific reasons for antipsychotic discontinuation or continuationfrom patients or clinicians perspectives. This study aimed to assess the construct validity of2 new measures of the Reasons for Antipsychotic Discontinuation/Continuation (RAD):RAD-I (a structured interview assessing the patients perspective) and RAD-Q (aquestionnaire assessing the clinicians perspective).
Methods:
Data were used from a 12-week antipsychotic trial of schizophrenia patients in which theRAD was administered at study entry and at study completion (or discontinuation). Constructvalidity was assessed through comparisons of RAD responses, clinicians responses to astandard patient disposition form identifying reasons for patients study discontinuation, andseveral standard psychiatric measures. Percent agreement quantified the correspondencebetween patient and clinician scores.
Results:
Patients indicating lack of improvement/worsening of positive symptoms as a somewhat toprimary reason for medication discontinuation had statistically significantly lessimprovement in Positive and Negative Syndrome Scale positive score than patients notreporting these as a reason (concurrent validity). Similar results were observed for the RADnegative symptom, functional, social support, and adherence items, whereas the mood andcognitive items were not significantly associated with change scores on standard psychiatricmeasures. Responses to the RAD were also weakly associated with variables thattheoretically should not be related to them (divergent validity). Level of agreement betweenthe clinician- and patient-rated RAD scores was high (60%-100%).
Conclusions:
Initial validation of the RAD suggests that the instruments are valid tools for gatheringdetailed information regarding reasons for antipsychotic discontinuation and continuationfrom patients and clinicians perspectives.