Elsevier

Psychiatry Research

Volume 260, February 2018, Pages 432-438
Psychiatry Research

Efficacy of bright light therapy in bipolar depression

https://doi.org/10.1016/j.psychres.2017.12.020Get rights and content

Highlights

  • BLT administered as an add-on therapy for BD is significantly superior to placebo.

  • BLT is not different from placebo with regards to side effects.

  • The antidepressant effects of BLT emerge in the first week.

  • Since BLT is fast-acting option, it may facilitate recovery in the acute phase of BD.

  • It may increase remission rates by improving treatment compliance through fast action.

Abstract

For 30 years, bright light therapy (BLT) has been considered as an effective, well-tolerated treatment for seasonal affective disorder (SAD). Because of low response rates, new treatment strategies are needed for bipolar depression (BD), which resembles SAD in certain respects. Few placebo-controlled studies of BLT efficacy have been carried out for BD. Accordingly, this study evaluates the efficacy and safety of BLT as an add-on treatment for BD. Thirty-two BD outpatients were randomly assigned to BLT (10000 lx) or dim light (DL, < 500 lx). During a two-week period, light was administered each morning for 30 min. The Hamilton Rating Scale for Depression and the Montgomery-Ǻsberg Depression Rating Scale assessed clinical outcome, and the UKU Side Effects Rating Scale evaluated side effects. No significant difference was observed in baseline depression scores in the two groups. Response rates for BLT and DL were 81% and 19%, and remission rates were 44% and 12.5%, respectively. Analyses showed statistically significant reductions in depression scores for the BLT group compared with the DL group on all scales. Side effects were similar in both groups, with headache as the most common side effect. The results suggest that BLT is an effective and safe add-on treatment for BD.

Introduction

Bipolar disorder (BPD) is a chronic mental disorder that includes recurring episodes of mania and depression with a significant effect on functioning and quality of life (Angst, 2007). Patients with BPD suffer mostly from depression. Bipolar I patients spend three times and bipolar II patients spend four times more days in depression than in mania (Kupka et al., 2007). Current treatment options for bipolar depression have low response rates, slow onset action beginning on average in two to eight weeks, and many side effects (Tseng et al., 2016). Taking into consideration that 30% of all bipolar patients report suicide attempts during depressive episodes and that treatment responses in a significant ratio of patients are still low despite mood stabilizers, antidepressants, and atypical antipsychotics, which have recently provided evidence-based results for treatment, there is an obvious need for more effective, safe and fast-acting treatment modalities in this patient group (Köhler et al., 2014, Musetti et al., 2013, Tondo et al., 2016).

Bipolar depression (BD) usually follows a seasonal rhythm, is recurrent, may present with atypical depressive symptoms, is usually cyclical and has an etiology in which mainly biological factors play a role. In this respect, seasonal depression and bipolar depression seem to share many common features (Geoffroy et al., 2014, Geoffroy et al., 2015). Both of these disorders are thought to share common factors in etiopathogenesis as well as in clinical presentation. As an example, there are significant dysregulations in melatonin secretion, disruptions in sleep-wake cycles and circadian rhythm in almost all BPD patients during illness episodes (Tseng et al., 2016). Also, a number of studies have showed that 11–50% of patients with seasonal depression actually have BPD (Sohn and Lam, 2004).

Seasonal affective disorder (SAD) was initially defined by Rosenthal et al. in 1984 as a clinical morbidity with a cyclical course that presents with atypical symptoms such as hypersomnia, increase in appetite, carbohydrate cravings and psychomotor retardation that present in winter months and wane in summer. Studies have shown that this subtype of depression responds well to light therapy (Nussbaumer et al., 2015, Rosenthal et al., 1984). The etiology of SAD seems to be related to insufficient daylight exposure resulting in melatonin excretion irregularities and disruptions in the circadian rhythm in genetically predisposed individuals (Pail et al., 2011). Although the exact mechanism of action of bright light therapy (BLT) is still unclear, due to the high rates of effectiveness in SAD it is presumed that it regulates the circadian rhythm by acting through several mechanisms, and reinforces the delayed phase by inhibiting melatonin (Nussbaumer et al., 2015).

BLT is seen as an effective, fast-acting and well-tolerated treatment for SAD (Rosenthal et al., 1984), and although still questionable in non-seasonal types of depression, many studies have reported it to be effective and as a treatment option for BD (Oldham and Ciraulo, 2014). The study rationale of our current research rests on the hypothesis that given the similarities of the presenting symptoms, BLT can be an effective treatment modality for BD as it is for SAD.

The number of randomized controlled studies on the effectiveness of BLT for bipolar depression is very limited, contrary to the abundance of studies done with regard to SAD (Geoffroy et al., 2015, Tseng et al., 2016). Since many patients with bipolar disorder have to be on a number of medications for long-term treatment, the availability and efficiency of a fast-acting and a comparably safer form of treatment must be extensively studied (Terman and Terman, 2005).

Based on these findings, we carried out a 2-week randomized single-blind placebo-controlled study to evaluate the efficacy of bright light therapy exposure in the mornings as an add-on therapy. The aims of the study were to assess the remission and the response rates, to evaluate the safety of BLT and to determine its effect on sleep quality. The hypotheses of this study are: 1) BLT as add-on therapy is expected to be significantly more effective than DL for bipolar depression; 2) BLT is expected to be similar to placebo in terms of side effects, 3) because of its effects on circadian rhythm BLT is also expected to improve the patient's sleep quality.

Section snippets

Materials and method

This study was conducted at Marmara University, from 2013 to 2014, and approved by Medical Faculty Ethics Committee of Marmara University. Patients were recruited from the Outpatient Clinic and the Bipolar Disorder Clinic in Marmara University Pendik Research and Training Hospital and recruitment period was limited to one year. Since the number of randomized controlled studies on the effectiveness of BLT on bipolar depression is very limited, contrary to the abundance of studies done on SAD, we

Results

Thirty-two patients who met the inclusion criteria were enrolled in the study. Patients were randomly assigned to two groups: 16 patients in study group receiving BLT with an intensity of 10000 lx, and 16 patients in the placebo group receiving light intensity less than 500 lx. Sociodemographic characteristics of the patients are presented in Table 1. There were no significant differences between the groups regarding age, education level and employment except sex. Female preponderance was

Discussion

This randomized, single blind study aimed to address the efficacy of BLT for bipolar depression when it is administered in the mornings for a two-week period and it has been found that both treatment response and remission rates in this treatment modality are significantly higher than dim-light with side effects seen similar to that of the placebo group.

Unipolar depression is a heterogeneous disorder with various symptom presentations and courses, clinical characteristics and etiopathogenesis

Acknowledgements

We appreciate the valuable assistance of Meltem Kora, M.D. and Banu Hummel Ph.D. in translating the article. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

References (38)

  • J. Angst

    The bipolar spectrum

    Br. J. Psychiatry

    (2007)
  • Y. Botanov et al.

    The acute side effects of bright light therapy: a placebo-controlled investigation

    PloS One

    (2013)
  • D.J. Buysse et al.

    Quantification of subjective sleep quality in healthy elderly men and women using the Pittsburgh Sleep Quality index (PSQI)

    J. Sleep. Res.

    (1991)
  • R.N. Golden et al.

    The efficacy of light therapy in the treatment of mood disorders: a review and meta-analysis of the evidence

    Am. J. Psychiatry

    (2005)
  • F.K. Goodwin et al.

    Manic-depressive Illness: Bipolar Disorders and Recurrent Depression

    (2007)
  • A.O. Kogan et al.

    Side effects of short-term 10,000-Lux light therapy

    Am. J. Psychiatry

    (1998)
  • S. Köhler et al.

    The challenge of treatment in bipolar depression: evidence from clinical guidelines, treatment recommendations and complex treatment situations

    Pharmacopsychiatry

    (2014)
  • R.W. Kupka et al.

    Three times more days depressed than manic or hypomanic in both bipolar I and bipolar II disorder

    Bipolar Disord.

    (2007)
  • O.U. Lingjaerde et al.

    The UKU side effect rating scale: a new comprehensive rating scale for psychotropic drugs and a cross‐sectional study of side effects in neuroleptic‐treated patients

    Acta Psychiatr. Scand.

    (1987)
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