56 A correlation was then observed between the magnitude of phase advances to morning LT and improvement in depression ratings, with maximum effects with phase advances of 1.5 to 2.5 hours (about 7.5 to 9 hours after the dim-light melatonin onset the evening
before).57 Since scores on the all targets Morningness Eveningness Questionnaire (MEQ) are strongly correlated with sleep midpoint and melatonin secretion, a predictive algorithm based on MEQ scores was then developed to define the individual optimal timing of LT administration,58 and proven successful Inhibitors,research,lifescience,medical even when used in common clinical settings, and when giving light in inhibitor Vismodegib combination with antidepressants.59 Over the years, other treatment algorithms
have been proposed,60 and research is currently identifying Inhibitors,research,lifescience,medical the most effective treatment schedule as a function of seasonality and other individual characteristics.61 Given that LT is, however, useful, even when given at midday,62 the clinical use of LT followed a pattern of evolving applications in any kind of depressive syndrome.63 The APA Committee on Research on Psychiatric Treatments64 and a Cochrane review65 concluded Inhibitors,research,lifescience,medical that light treatment for nonseasonal major depression is efficacious, with effect sizes equivalent Inhibitors,research,lifescience,medical to those in most antidepressant pharmacotherapy trials. When combined with standard antidepressant drug treatments LT hastens recovery, with benefits that can be perceived by the patients during the first week of treatment.59,66 After 1 month of treatment, patients treated with light show a net benefit, in respect to placebo, that can be quantified in a approximately 30% better reduction in the severity of depression: remarkably, these values are very
similar for early studies performed with the combination of light and tricyclic antidepressants, and Inhibitors,research,lifescience,medical for new studies combining light and selective serotonergic Cilengitide drugs.59,66,67 The benefit is also clinically evident in drug-resistant patients, when adding light to ongoing albeit ineffective antidepressants.68 Similar to SD, LT in nonseasonal major depression does not show a sustained effect after discontinuation, with a complete offset of effect after 1 month,69 but the relapse can be easily prevented when combining LT with common antidepressant drugs.70 Again, similarly to SD, LT caused marked benefits in the broadly defined depressive syndrome, including very different psyehopalhological conditions such as antepartum depression71 as well as post-stroke depression in the elderly.