Efficacy of Daylight as Adjunctive Treatment in Patients With Unipolar Depression - a Randomized Controlled Feasibility Study

Due to inadequate efficiency of existing medical and psychotherapeutic treatments for depression there is a need for investigating the efficacy of adjunctive treatments. Light therapy has proven efficient as an add-on treatment for depression, but some patients might prefer being outdoors rather than sitting in front of a light therapy screen. However, no high-quality studies, have so far investigated the antidepressant and other potential positive effects of regular exposure to morning daylight for patients with unipolar depression.

The aim of this study is to examine the efficacy of morning daylight as add-on to treatment as usual in patients with depression. Efficacy is measured as reduction of depressive symptoms, improvement of sleep quality, and improvement of well-being.

Methods and material: A randomized controlled trial comprising 150 patients diagnosed with unipolar depression aged 18-50 years will be conducted. Patients are included after giving informed consent and the study period is 6 weeks. A wearable Personal Light Tracker, measuring the amount off light received, will be provided for all participants. Participants will be randomized into the following groups:

Group 1: Daylight (outdoor daylight exposed stay for minimum 30 minutes per day before 1 pm). To motivate patients to go outside they will receive psychoeducation on the connection between exposure to morning daylight and a possible antidepressant effect, and they are introduced to potential options for outdoor activities. A detailed instruction to the personal light tracker and the matching app, for monitoring the amount of light received throughout the day, is provided.

Group 2: Control group receiving treatment as usual. Patients will wear a personal light tracker but they are not introduced to the light-monitoring-app.