1 Since then, numerous studies have not only proven its efficacy, but also greatly refined our knowledge on treatment strategies, thereby allowing for astonishingly high response rates of 80% in selected patient populations.5 BIT is safe,

effective, and it has few and benign side effects. It is generally well accepted by the patients,6 and indications other than SAD, eg, disturbances Inhibitors,research,lifescience,medical of GDC-0994 clinical trial circadian rhythm due to jet lag or shift work,7,8 circadian-phase-related disturbances in dementia,9,10 sleep disorders,11,12 and nonscasonal affective disorders,13-15 are expanding research fields. Table II. Guidelines for bright light therapy (BLT). Efficacy The first controlled clinical trial1 already showed the beneficial effects of light against symptoms of SAD. Siiuv then, more than 60 controlled studies and two mekianalyscs16,17 have shown the efficacy of this treatment. Using stringent criteria, the meta-analysis of Terms n e! al16 found remission rates of up Inhibitors,research,lifescience,medical to 67% of patients wii h milder depression and up to 40% of more severely depressed patients. These benefits were seen as early- us 1 week after beginning treatment. However, it is now known that improvement may sometimes be seen as late as 2 to 4 weeks after beginning Inhibitors,research,lifescience,medical BIT.18 The obvious obstacles in the search for plausible

placebos and “blinded” designs for studying the efficacy of BLT have led to concerns about the adequacy of control conditions. Early studies mostly used dim-light of an intensity of 300 lux or less, delivered through a light source otherwise identical to that used in the active condition (mostly light of 2500 lux intensity). As it was still possible Inhibitors,research,lifescience,medical to distinguish between the bright and dim-light conditions, these studies

have been questioned as to whether they measured real biological effects and whether they could reliably separate a true antidepressant effect from placebo effects. However, fantasy and creativity of researchers in the field Inhibitors,research,lifescience,medical has led to further studies, which now unequivocally prove that light is an active biological agent with antidepressant effects in SAD. Some of these studies used (deactivated) negative ion generators as placebo condition.18-20 Like a light PAK6 box, the negative ion generator is a device, has a plausible mechanism of antidepressant action, and requires the subject to sit beside it. Light had the better antidepressant effect and produced significantly more remissions, although expectations were equal for both conditions. Interestingly enough, high doses of negative ions do seem to have an antidepressant effect as well.20 Another challenge for efficacy studies on light therapy is the “light-noise” inevitably encountered in a normal living environment. Depending on weather conditions, outdoor light intensities can easily surmount the intensities delivered by a light box, even in the winter.