Abstract
PURPOSE: Depressive disorders cause a major burden of disease worldwide and often lead to a loss of social functioning. Patients suffering from depressive disorders report a lower quality of life (QOL) than people without a history of mental health issues. Internet-based interventions (IBIs) based on cognitive behavioral therapy (CBT) are effective in reducing symptom severity but data on their impact on quality of life in clinically depressed patients so far is scarce. METHODS: Selfapy is a CBT-based IBI for depressive disorders. 401 participants (332 female, mean age 37 (SD = 11) with a diagnosis of major depressive disorder (MDD) or dysthymia were enrolled in a randomized, parallel, three-arm trial comparing a therapist-guided Selfapy intervention with an unguided Selfapy intervention and a waiting list control. QOL was measured using the WHOQOL-BREF at baseline, post-treatment (12 weeks) and at 24-week follow-up. The effects of the interventions on QOL were calculated using linear mixed effects models. RESULTS: At post-treatment (12 weeks) the guided and unguided intervention groups reported an increase in QOL on physical and psychological health domains compared to controls (significant group*time interaction). The gain in QOL was maintained over the follow-up period only for psychological health. QOL decreased in the social relationships and environment domains over the course of treatment and during the follow-up treatment for all participants. There were no differences between the guided and the unguided intervention. CONCLUSION: Selfapy proved to positively affect psychological and physical QOL in a sample of participants suffering from depressive disorders and can therefore be considered an effective and highly scalable therapeutic tool. The pattern of results might partly be attributable to effects of the COVID-19 pandemic and public health measures that coincided with the trial. TRIAL REGISTRATION: German Clinical Trials Register (DRKS): DRKS00017191. Registered June 14th, 2019, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00017191 .