The effects of bright light treatment via ear canals on quality of sleep and depressive mood among overworked employees: A randomized-controlled clinical trial

Abstract

Many overworked employees need tools to improve their depressive mood or sleep disorder. In Finland, a new device of bright light therapy was developed. Our objective was to evaluate the effect of bright light treatment via ear canals on improving the depressive mood and sleep disorder. We conducted a randomized, controlled, crossover designed, open-label trial. We examined 27 participants aged 23-52 years, assigned to either Early treatment or Later treatment groups. The Early treatment group used the device on weekdays for the first 4 weeks, followed by a 4-week observation period. The Later treatment group had an observation period for the first 4 weeks, followed by device treatment for the subsequent 4 weeks. Every Friday, the participants were asked to answer questionnaires: A Self-rating Depression Scale (SDS), an Athens Insomnia Scale (AIS), and a Profile of Mood States (POMS) Brief Form. While no significant effect was found on the SDS following treatment (p = 0.16), the AIS showed a significant improvement (p = 0.004), and the scores for the Depression (D) and Vigor (V) of POMs decreased significantly (p = 0.045, p = 0.006, respectively). Bright light treatment via ear canals may improve sleep quality and depressive mood.