Background: Although a large number of adults with intellectual disabilities have depressive symptoms, non-pharmacological treatments are scarce. The present authors investigated whether bright light therapy (BLT) is effective in decreasing depressive symptoms compared to care as usual.
Methods: This multicentre randomized controlled trial consisted of three study groups (10,000 lux BLT, dim light BLT and a no-BLT group). Participants received BLT for 30 min in the morning (14 consecutive days), additional to their regular care. Primary outcome was as follows: depressive symptoms measured with the ADAMS Depressive Mood subscale 1 week after the end of BLT (same time period in the no-BLT group).
Results: Forty-one participants were included in our trial. In both BLT groups, a significant decrease in depressive symptoms was seen. No significant differences were found between 10,000 lux BLT and no-BLT (p = .199) and no significant differences between dim light BLT and no-BLT (p = .451). A minimum amount of side effects and no adverse events were reported.
Conclusions: In both BLT interventions, a decrease in depressive symptoms was seen. With 10,000 lux BLT, depressive symptoms decreased even below the clinical cut-off point, which makes BLT a promising intervention for clinical practice.
Keywords: bright light therapy; depressive symptoms; intellectual disabilities; randomized controlled trial.
© 2020 The Authors. Journal of Applied Research in Intellectual Disabilities published by John Wiley & Sons Ltd.