Effects of online intervention for depression on mood and positive symptoms in schizophrenia

Depression is common in schizophrenia. Whereas the improvement of mood and self-esteem represents a subjective treatment priority for many patients, depression is rarely a primary target for clinical intervention. The present trial examined whether an online intervention for depression can ameliorate depressive symptoms in schizophrenia.

A total of 58 individuals with schizophrenia were invited to participate in an online survey which encompassed the Center for Epidemiologic Studies-Depression Scale (CES-D, primary outcome), the Patient-Health-Questionnaire-9 (PHQ-9) and the Paranoia Checklist. Subsequently, telephone interviews were conducted to verify diagnostic status and assess symptoms (Positive and Negative Syndrome Scale, PANSS). Participants were randomized either to the experimental condition (online depression intervention) or to a waitlist control condition. Three months after inclusion, a reassessment was carried out (self-report and telephone interview blind for group condition). The trial was registered (registration: DRKS00007888).

Participants in the treatment group showed a significant decline of depressive symptoms at a medium-to-large effect size, as assessed with the CES-D and the PANSS depression item, in comparison to the waitlist control group (completer (CC) and intention-to-treat analyses (ITT)). For the PHQ-9 (CC and ITT) and the PANSS distress subscale (CC only) significance was bordered at a medium effect size. Completion at the post-assessment after three months was 84%.

Depression in schizophrenia is both underdiagnosed and undertreated. To reduce the large treatment gap in the disorder, low threshold strategies are urgently needed. Online treatment and bibliotherapy may represent valuable tools to address patients' needs beyond the treatment of the core positive syndrome.