A CONTROLLED COMPARISON OF LIGHT BOX AND HEAD-MOUNTED UNITS IN THE TREATMENT OF SEASONAL DEPRESSION

Background: Patterns of response to the light box and head-mounted uni t (HMUs) in seasonal affective disorder (SAD) appear to differ. The cu rrent study employed a ''no light'' condition to compare the response rates with the light box and HMU against a plausible placebo. Method: Forty-three subjects with DSM-III-R nonpsychotic, unipolar major depre ssion, seasonal subtype, were randomly assigned, in a double-blind man ner, to receive 2 weeks of active treatment with a light box (N = 9) o r HMU (N = 12) that emitted visible light, or 2 weeks of placebo treat ment with a light box (N = 12) or HMU (N = 10) that emitted no visible light. Re sponse was defined as a 50% or greater reduction in both th e 17-item ''typical'' score and 8-item ''atypical'' score on the Struc tured Interview Guide for the Hamilton Rating Scale for Depression-SAD version (SIGH-SAD). Results: Using ANOVA for repeated measures, with change in total SIGH-SAD score as the dependent measure, we found no s ignificant main effect of light (F = 0.20, p = N.S.) or unit (F = 0.50 , p = N.S.), and no interaction (F = 0.21, p = N.S). Using log-linear analysis, we found no significant difference in response rate between the four cells (likelihood ratio chi(2) = 2.1, P = N.S.). Using chi-sq uare analysis, we found no significant difference in response rates be tween patients who received light (48%) versus patients who received n o light (41%; chi(2) = 0.2, P = N.S.) or between patients who received the light box (38%) versus HMU (50%; chi(2) = 0.62, P = N.S.). Conclu sion: The failure to detect any significant difference in efficacy bet ween active and placebo treatments calls into question the specificity of light in light therapy for SAD. Methodological limitations, partic ularly small sample size, are discussed.