Light therapy for seasonal affective disorder with blue narrow-band light-emitting diodes (LEDs)

Biol Psychiatry. 2006 Mar 15;59(6):502-7. doi: 10.1016/j.biopsych.2005.07.006. Epub 2005 Sep 13.


Background: While light has proven an effective treatment for Seasonal Affective Disorder (SAD), an optimal wavelength combination has not been determined. Short wavelength light (blue) has demonstrated potency as a stimulus for acute melatonin suppression and circadian phase shifting.

Methods: This study tested the efficacy of short wavelength light therapy for SAD. Blue light emitting diode (LED) units produced 468 nm light at 607 microW/cm2 (27 nm half-peak bandwidth); dim red LED units provided 654 nm at 34 microW/cm2 (21 nm half-peak bandwidth). Patients with major depression with a seasonal pattern, a score of > or =20 on the Structured Interview Guide for the Hamilton Depression Rating Scale-SAD version (SIGH-SAD) and normal sleeping patterns (routine bedtimes between 10:00 pm and midnight) received 45 minutes of morning light treatment daily for 3 weeks. Twenty-four patients completed treatment following random assignment of condition (blue vs. red light). The SIGH-SAD was administered weekly.

Results: Mixed-effects analyses of covariance determined that the short wavelength light treatment decreased SIGH-SAD scores significantly more than the dimmer red light condition (F = 6.45, p = .019 for average over the post-treatment times).

Conclusions: Narrow bandwidth blue light at 607 microW/cm2 outperforms dimmer red light in reversing symptoms of major depression with a seasonal pattern.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Aged
  • Circadian Rhythm
  • Color
  • Equipment Design
  • Equipment Safety
  • Female
  • Humans
  • Luminescence
  • Male
  • Middle Aged
  • Personality Inventory
  • Photometry
  • Phototherapy / instrumentation*
  • Proportional Hazards Models
  • Psychometrics
  • Radiation, Nonionizing
  • Radiometry
  • Seasonal Affective Disorder / diagnosis
  • Seasonal Affective Disorder / psychology
  • Seasonal Affective Disorder / therapy*