Adjunctive Bright Light Therapy in Patients With Bipolar Depression and Eveningness

Inclusion Criteria: 1. Aged 18-65 years. 2. Is capable to give informed consent. 3. Meeting the diagnostic criteria of bipolar depression (including both bipolar I and II disorders) by the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-V), Disorders (SCID-V). 4. a score 20 or above representing current moderate or severe episode of major depression and a score of at least 1 on items H1 or H2 on the Structured Interview Guide for the Hamilton Depression Rating Scale with Atypical Depression Supplement (SIGH-ADS), corresponding to at least moderate severity. 5. A score of 41 or less by the Morningness-Eveningness Questionnaire which represents eveningness. 6. On a stable dose of antimanic treatment for bipolar disorder for at least four weeks. Exclusion Criteria: 1. Major Depressive Disorder fulfilling the Seasonal Pattern Specifier of the DSM-V (Seasonal Affective Disorder). 2. A past history of rapid-cycling within the past twelve months or a Young Mania Rating Scale more than 12 at screening 3. A current or past history of schizophrenia, mental retardation, organic mental disorder; or current substance use disorder. 4. Presence of psychotic symptoms or substantial suicidal risk as judged by the clinician and/or screening instruments. 5. Presence of contraindications to bright light therapy: for example, history of light induced migraine/ epilepsy; current use of photosensitizing medications such as St. John's wart; presence of eye disease: e.g. retinal blindness, severe cataract, glaucoma, and photosensitive skin condition e.g. systemic lupus erythematosus 6. Significant medical condition/ hearing impairment/ speech deficit leading to incapability of completing clinical interview. 7. Regular shift-workers or trans-meridian flight in the past 3 months or during study 8. Enrolment in another clinical trial of an investigational medicinal product or device. 9. Receiving regular psychotherapy.