Predictors of attrition during acute pharmacotherapy of psychotic depression in a clinical trial

Little is known about factors that contribute to attrition in clinical trials of the pharmacotherapy of psychotic depression. The purpose of this study was to identify factors associated with attrition during acute pharmacotherapy in the Study of the Pharmacotherapy of Psychotic Depression II (STOP-PD II) clinical trial. Sociodemographic and clinical variables were assessed at baseline in 269 men and women, aged 18-85 years, who were treated with up to 12 weeks of open-label sertraline plus olanzapine. Univariate analyses examined the association of baseline variables with overall non-completion, as well as reasons for non-completion. Logistic regression was used to model the relationship of the significant univariate predictors with non-completion and its reasons. Seventy-four (27.5 %) participants did not complete the acute treatment phase of STOP-PD II. Male gender, younger age, inpatient status, higher Clinical Global Impression (CGI) severity of illness, and higher severity of psychomotor disturbance were associated with non-completion in univariate analyses. In regression models, higher CGI severity of illness score was the only significant independent predictor of non-completion, explained by withdrawal of consent. Our findings have implications for the retention of persons with psychotic depression in clinical trials.