Psychoticism and Paranoid Ideation in Patients With Nonpsychotic Major Depressive Disorder: Prevalence, Response to Treatment, and Impact on Short- and Long-Term Treatment Outcome

Objective/Introduction: We sought to characterize the impact of the 90-item Symptom Checklist (SCL-90) subscales for paranoid ideation (PI) and psychoticism (P) in patients with major depressive disorder (MDD), on acute antidepressant response and on relapse prevention. Subjects with Structured Clinical Interview for DSM Disorders-diagnosed nonpsychotic MDD were recruited into a clinical trial of open-label fluoxetine 10-60 mg/day for 12 weeks, followed by double-blind randomization of responders (n=262) to fluoxetine continuation or placebo for 12 months. PI and P were assessed with the patient-rated SCL-90. The association of these symptoms with response to treatment was assessed by logistic regression. We found significant decreases in PI and P during acute treatment phase for fluoxetine responders and nonresponders, although only 10.3% and 7.5% of patients experienced a >50% reduction in PI and P scores, respectively. Neither PI nor P scores significantly predicted time to relapse. P scores predicted a lower response rate to treatment with fluoxetine. The results of the present study suggest that there is a significant relationship between the presence of psychoticism in patients with nonpsychotic MDD, and the likelihood of overall depressive symptom improvement following a trial of monotherapy with fluoxetine. An increased burden of psychoticism in depressed subjects may confer poorer response to fluoxetine, but not increased risk of relapse among fluoxetine responders.