Amin A Muhammad Gadit.
Light therapy: does it play an important role in mental health?.
J Pak Med Assoc Jan ;62(5):511-2.

According to Lam1 based on his observations, research and literature review, initial use of light therapy in psychiatry arose from circadian rhythm hypotheses for seasonal and non-seasonal depression. Suppression of human melatonin generally requires greater than 2,000 lux in terms of intensity of light. Exposure of patients to 2,500 lux white light for three hours in the morning and three hours in the evening may confer beneficial effects on mood. It is further suggested that there are no absolute contraindications to light therapy and there is no evidence that it would cause ocular or retinal damage. However, patients with ocular risk factors should have baseline ophthalmological consultation prior to starting light therapy. In a double-bind randomized controlled trial, patients who underwent three weeks of pale blue Bright Light Therapy showed significantly improved depression scores and sleep patterns compared with those who received placebo through dim red light and a 81% difference in increased melatonin levels.2 It was concluded in the same study that in elderly patients with major depressive disorder, Bright Light Therapy improved mood, enhanced sleep efficiency and increased the upslope of melatonin level gradient. Another analysis of randomized, controlled trials suggests that bright light treatment and dawn stimulation for seasonal affective disorder and bright light for nonseasonal depression are efficacious with effect sizes equivalent to those in most antidepressant pharmacotherapy trials.3 A book review described atypicality of seasonal affective disorder and marked improvement within four to five days of beginning light treatment.4 A Canadian randomized controlled trial on effectiveness of light therapy and fluoxetine in patients with Seasonal Affective Disorder (SAD) concluded, that light treatment showed earlier treatment response onset and lower rate of some adverse events relative to fluoxetine but there were no other significant differences in outcome.

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