Article

The phototherapy light visor: More to it than meets the eye

Department of Psychiatry, Harvard Medical School, Boston, USA.
American Journal of Psychiatry (Impact Factor: 13.56). 09/1995; 152(8):1197-202.
Source: PubMed

ABSTRACT The purpose of the study was to ascertain whether phototherapy light visors provide an effective treatment for seasonal affective disorder. Previous studies have demonstrated a moderate response rate but have failed to find any difference in efficacy between light intensities.
Subjects were randomly assigned to receive, over a 2-week treatment period, 30 minutes of morning phototherapy with a light visor that emitted either a dim (30-lux) red light or a bright (600-lux) white light. Raters were blind to treatment, and patients were unaware of the alternatives. Response was assessed by using the structured 21-item Hamilton Depression Rating Scale, with an eight-item addendum for atypical depressive symptoms. Fifty-seven patients were enrolled across two sites.
Patients assigned to the different visors had similar baseline depression scores and similar expectations of outcome. Hamilton depression scale scores declined by 34.6% for subjects given bright white light and by 40.9% for subjects given dim red light. Scores for atypical depressive symptoms fell by 44.1% for patients assigned the bright white light visors and by 49.0% for patients assigned the dim red light visors. Altogether, 39.3% of the patients who received red light and 41.4% of the patients who received bright white light showed a full clinical response.
There were no significant differences in therapeutic response between patients who were treated with red or white light. The results of this study suggest that the phototherapy light visor may function as an elaborate placebo. Alternative explanations, however, are considered.

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    • "The evaluations of initial expectancy scores in the visor studies indicated that the patients had the same expectations for therapeutic effects of proposed active and placebo treatments (i.e. Teicher et al. 1995). Consequently, these results of the studies with headmounted devices showed that clinical outcome is not related to intensity, color or duration of light. "
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    Biological Rhythm Research 12/2005; 36(5). DOI:10.1080/09291010500218506 · 1.22 Impact Factor
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    • "To our knowledge, only six studies have examined the antidepressant response to bright light therapy with a credible placebo control treatment that produced similar expectations for improvement as the bright light treatment. Three of these studies used head-mounted light visors and compared bright white light to dimmer light (Joffe et al., 1993; Rosenthal et al., 1993; Teicher et al., 1995). Another study used head-mounted light visors but compared bright red light to dimmer red light (Levitt et al., 1994). "
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    ABSTRACT: Bright light is the recommended treatment for winter seasonal affective disorder (SAD). Previously we showed that the antidepressant effect of morning (but not evening) light was greater than placebo after 3 weeks of treatment. Here, we determined if the magnitude and direction of circadian rhythm phase shifts produced by the bright light in the previous study were related to the antidepressant effects. Twenty-six SAD patients from the original sample of 96 had their rectal temperature continuously monitored while they participated in a placebo-controlled parallel design conducted over six winters. After a baseline week, there were three treatments for 4 weeks-morning light, evening light, or morning placebo. Bright light was produced by light boxes (approximately 6000 lux). Placebos were sham negative ion generators. All treatments were 1.5 h in duration. Depression ratings were made weekly by blind raters. Circadian phase shifts were determined from changes in the timing of the core body temperature minimum (Tmin). Morning light advanced and evening light delayed the Tmin by about 1 h. The placebo treatment did not alter circadian phase. As the sleep schedule was held constant, morning light increased and evening light decreased the Tmin to wake interval, or phase angle between circadian rhythms and sleep. Phase advance shifts and increases in the phase angle were only weakly associated with antidepressant response. However, there was an inverted U-shaped function showing that regardless of treatment assignment the greatest antidepressant effects occurred when the phase angle was about 3h, and that patients who moved closer to this phase angle benefited more than those who moved farther from it. However 46% of our sample had a phase angle within 30 min of this 3 h interval at baseline. So it does not appear that an abnormal phase angle can entirely account for the etiology of SAD. A majority (75%) of the responders by strict joint criteria had a phase angle within this range after treatment, so it appears that obtaining the ideal phase relationship may account for some, but not all of the antidepressant response. In any case, regardless of the mechanism for the antidepressant effect of morning light, it can be enhanced when patients sleep at the ideal circadian phase and reduced when they sleep at a more abnormal circadian phase.
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    • "Head mounted light devices may overcome these difficulties associated with light boxes. The greatest use of head mounted light devices has been in the treatment of seasonal affective disorders (SAD) [Stewart et al., 1990; Joffe et al., 1993; Rosenthal et al., 1993; Levitt et al., 1994; Teichner et al., 1995; Zammit et al., 2000]. Although a phase shifting hypothesis has been proposed for SAD [Lewy et al., 1998], none of these "
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