Objectives: We investigated the clinical benefits of bright light therapy (BLT) as an adjunct treatment to ongoing psychopharmacotherapy, both in unipolar and bipolar difficult-to-treat depressed (DTD) outpatients.
Methods: In an open-label study, 31 depressed outpatients (16 unipolar and 15 bipolar) were included to undergo 3 weeks of BLT. Twenty-five completed the treatment and 5-week follow-up.
Main outcome measures: Clinical outcomes were evaluated by the Hamilton Depression Rating Scale (HDRS). The Snaith-Hamilton Pleasure Scale and the Depression Retardation Rating Scale were used to assess changes in anhedonia and psychomotor retardation, respectively.
Results: The adjunctive BLT seemed to influence the course of the depressive episode, and a statistically significant reduction in HDRS scores was reported since the first week of therapy. The treatment was well-tolerated, and no patients presented clinical signs of (hypo)manic switch during the overall treatment period. At the end of the study (after 5 weeks from BLT discontinuation), nine patients (36%, eight unipolar and one bipolar) still showed a treatment response. BLT augmentation also led to a significant improvement of psychomotor retardation.
Conclusion: BLT combined with the ongoing pharmacological treatment offers a simple approach, and it might be effective in rapidly ameliorating depressive core symptoms of vulnerable DTD outpatients. These preliminary results need to be confirmed in placebo-controlled, randomized, double-blind clinical trial on larger samples.
Keywords: anhedonia; bipolar depression; light therapy; psychomotor dysfunction; unipolar depression.