Augmentation of drug treatment with bright light therapy in patients with difficult-to-treat depression: acute and long term observation

Background/Aims: Difficult-to-treat depression (DTD) represents a common challenge for clinicians who often must develop more efficacious treatment approach focusing on multidisciplinary competences and augmentation strategies. A growing number of clinical studies support the usefulness of chronotherapeutic interventions, such as light therapy (LT), in the treatment of major depression. In this study, we investigated the benefi ts of LT in DTD patients alongside ongoing medication and examined the added effectiveness of the combined treatment protocol both in the acute phase and during a long-term observation. Methods: Nineteen DTD outpatients, both unipolar and bipolar, affected by a major depressive episode were treated by LT (10.000 lux, 30 min daily for 3 weeks) combined with ongoing antidepressant or mood stabilizer drug treatment. Difficult-to-treat depression was identified according to Rush criteria. Effectiveness was rated using the 21-items Hamilton Depression Rating Scale (HDRS) and the Visual Analogue Scale (VAS) over 3 weeks. A prospective 12-month follow up visit was programmed to check the recurrence of a depressive episode. Results: Significant improvements of depressive symptoms were observed in both objective (HDRS) and subjective mood ratings (VAS). Seven patients (36,8%) were in remission (50% or greater changes in HDRS) 2 months after starting LT treatment and five of them (71,4%) maintained this responsiveness at one year follow-up. Repeated measures analysis of variance with changes in the HDRS scores as dependent variable and with time as independent factors showed a significant improvement in depressive symptoms over time (F(5, 75)=9,378; p=0.000). A Bonferroni correction, used to make post hoc analysis, confirm a significant reduction in HDRS scores since week 1 of LT (p<0.02). Discussion: The study results support the usefulness of LT as an adjunct treatment in DTD patients. When combined with ongoing medication, LT induced a rapid improvement in depressive symptoms and could be helpful in triggering an acute response without early relapse.