Recent quotes:

Early birds less prone to depression: Largest study yet links chronotype to mental health -- ScienceDaily

In 2009, all the participants included in the study were free of depression. When asked about their sleep patterns, 37 percent described themselves as early types, 53 percent described themselves as intermediate types, and 10 percent described themselves as evening types. The women were followed for four years to see who developed depression. Depression risk factors like body weight, physical activity, chronic disease, sleep duration, or night shift work were also assessed. The researchers found that late chronotypes, or night owls, are less likely to be married, more likely to live alone and be smokers, and more likely to have erratic sleep patterns. After accounting for these factors, they found that early risers still had a 12 -- 27 percent lower risk of being depressed than intermediate types. Late types had a 6 percent higher risk than intermediate types ( this modest increase was not statistically significant.) "This tells us that there might be an effect of chronotype on depression risk that is not driven by environmental and lifestyle factors," said Vetter.

Color-Changing LEDs Could Reset the Circadian Rhythm - The Atlantic

Hints of positive impacts have emerged in Texas, too, where tunable LED systems have been installed in some elementary and middle-school classrooms in Carrollton, a northern suburb of Dallas. A September DOE report on the Carrollton systems suggested that the tunable LED system had improved the overall learning environment—though the DOE noted that empirically measuring the effects of the circadian lights was beyond the scope of the project. Back in Washington, entire schools—including two Renton high schools and a brand new middle school—now have circadian lighting, and initial data out of Lindbergh High School seemed to echo the findings in Texas: The school reported a double-digit rise in SAT test scores following installation of the tunable LEDs.

Chronobiological therapy for mood disorders: Expert Review of Neurotherapeutics: Vol 11, No 7

Alteration of the sleep–wake cycle and of the sleep structure are core symptoms of a major depressive episode, and occur both in course of bipolar disorder and of major depressive disorder. Many other circadian rhythms, such as the daily profiles of body temperature, cortisol, thyrotropin, prolactin, growth hormone, melatonin and excretion of various metabolites in the urine, are disrupted in depressed patients, both unipolar and bipolar individuals. These disrupted rhythms seem to return to normality with patient recovery. Research on circadian rhythms and sleep have led to the definition of nonpharmacological therapies of mood disorder that can be used in everyday practice. These strategies, named chronotherapeutics, are based on controlled exposures to environmental stimuli that act on biological rhythms, and demonstrate good efficacy in the treatment of illness episodes.