Light therapy’s effects on symptoms and body clock in nonseasonal mood disorders

Bright light therapy significantly improved clinical symptoms of depression in 27 unmedicated patients with nonseasonal depression.

• Bright light therapy enhanced scores on the Hamilton Rating Scale for Depression (HRSD), indicating reduced depressive symptoms.
• The timing of bright light exposure, whether in the morning or evening, did not affect its antidepressant effectiveness.
• Dim light therapy did not produce any significant changes in HRSD scores.
• Patients with nonseasonal depression showed greater sensitivity in their body temperature rhythms to bright light than normal volunteers.
• The changes in body temperature rhythms due to bright light were not linked to the observed clinical improvement in depression.

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