Dose relationships of morning bright white light in seasonal affective disorders (SAD)

Indirect bright light improves circadian rest-activity rhythm disturbances in demented patients

“…Lingjaerde et al 1993). Moreover, as several authors have suggested an interaction of light intensity and exposure duration (Kronauer and Czeizler 1993;Terman 1993;Wirz-Justice et al 1986), the cumulative dose of the whole-day bright light exposure in the present study may actually have been quite high. However, given the general deterioration of the visual system in the elderly, and the fact that Satlin et al (1992) found no improvement for agitation in demented patients treated with bright light of an intensity lower than 2000 lux, whereas agitation did improve in those studies where more than 2000 lux was applied (Hozumi et al 1990;Lovell et al 1995;Okawa et al 1989), an intensity of more than 2000 lux is recommended in future studies, even if this may be hard to accomplish with indirect lighting.…”

Response of the melatonin cycle to phototherapy for Seasonal Affective Disorder

“…However, the general result of increased clinical efficacy given light exposure in early morning (Terman, 1988) makes plausible the hypothesis of a differentially photosensitive reaction at that time of day. Several studies have shown that 30 minute exposures in early morning are, on average, less effective therapeutically than one-or two-hour durations (Hellekson, 1987;Terman et al, 1987;Wirz-Justice et al, 1987). [On the other hand, upon stabilization of the phase advance after several days of phototherapy at long duration, shorter exposures might become adequate for maintenance (A. J.…”

Pituitary volume and the effects of phototherapy in patients with seasonal winter depression: a controlled study

“…These results corroborate previous reports, showing that intensity and duration of exposure are important factors in the mechanism of action of phototherapy. [34][35][36] In addition, the efficacy of phototherapy with a bright light (10000 lux) during a 30-minute period adds the advantage of reducing the time of exposure to light, making it more practical and acceptable to patients.…”