title: Lux vs. wavelength in light treatment of Seasonal Affective Disorder.
abstract: OBJECTIVE
  Published dosing guidelines for treatment of Seasonal Affective Disorder (SAD) refer to photopic lux, which is not appropriate for short-wavelength light. Short wavelengths are most potent for many non-visual responses to light. If SAD therapy were similarly mediated, standards utilizing lux risk overestimating necessary dose. We investigated antidepressant responses to light using two light-emitting diode (LED) sources, each emitting substantial short-wavelength light, but <2500 lux.
  
  
  METHODS
  A randomized, double-blind trial investigated 3-week 45 min/day out-patient treatment with blue-appearing (goLITE) or blue-enriched white-appearing light in 18 moderately-depressed adults (12F, 49.1 +/- 9.5 years). Equivalent numbers of photons within the short-wavelength range were emitted, but the white source emitted twice as many photons overall and seven-fold more lux.
  
  
  RESULTS
  Depression ratings (SIGH-ADS; http://www.cet.org) decrease averaged 82% (SD = 17%) from baseline (P < 0.0001) in both white- and blue-light groups. Both sources were well tolerated.
  
  
  CONCLUSIONS
  Short-wavelength LED light sources may be effective in SAD treatment at fewer lux than traditional fluorescent sources.
authors.affiliation: Department of Psychiatry, Brigham & Women's Hospital and Harvard Medical School, Boston, MA 02115, USA. jlanderson@partners.org
authors.forename: J L
authors.initials: JL
authors.lastname: Anderson
authors.forename: C A
authors.initials: CA
authors.lastname: Glod
authors.forename: J
authors.initials: J
authors.lastname: Dai
authors.forename: Y
authors.initials: Y
authors.lastname: Cao
authors.forename: S W
authors.initials: SW
authors.lastname: Lockley
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017785:Photons; D010789:Phototherapy / Q000379:methods*; D016574:Seasonal Affective Disorder / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D055815:Young Adult