Diagnosis of unipolar or bipolar depression (seasonal or non-seasonal) as assessed with the Mini-International Neuropsychiatric Interview (M.I.N.I.)
A current depressive episode (a score of 6 or higher on the Quick Inventory of depressive symptomatology Self Report (QIDS-SR)
Sufficient knowledge of Dutch or English language to fill in questionnaires
Provided Informed consent
You may not be if
A current (hypo)manic or mixed episode (as assessed with the M.I.N.I.)
Current psychotic episode (as assessed with the M.I.N.I.)
Prominent active suicidality (score 10 or higher on the M.I.N.I. module)
Antidepressant therapy (medication, psychotherapy or BLT, or other forms of specific treatments for depression) that started less than 2 months prior to study entry
participants with bipolar disorder should be in mood-stabilizing treatment for at least 1 month in a recommended dosage,
Use of melatonin or agomelatine in the last month
Current use of antibiotics
Current use of light sensitivity increasing medication
Travelled across more than 1 time zone during past month or during the treatment
Travelled to sunny holiday locations/winter sports during past month
pre-existing eye and skin disorders (retinitis pigmentosa, porphyria, chronic actinic dermatitis and sun-induced urticaria)
Systemic disorders with potential retinal involvement (rheumatoid arthritis and systemic lupus erythematosus)
Suffering from colour blindness (assessed by Ishihara colour plates)
Participated in night shift work in the last three months
(Retinal) blindness, severe cataract and glaucoma
Light-induced migraine or epilepsy
Pregnancy, or parents with a child younger than 18 months old
