The Effect of Improving Sleep and Circadian Rhythms on Affective Symptoms In First Year Medical Students

There is a substantial and growing body of literature that has identified medical students as a group that suffers from increased levels of depression, anxiety, and other markers of "psychological distress". Other studies have demonstrated that in conjunction with the "psychological distress", medical students suffer from sleep deprivation, sleep disruption, and daytime sleepiness. Finally there is some preliminary evidence that residents and interns show increased symptoms of fatigue. It might reasonably be assumed that all of these symptoms are inter-related and more importantly detrimental to both the student and those patients under their care. There have been interventional studies aimed at educating participants on stress management, however these attempts have had only limited success.

Circadian rhythms are biological rhythms that contribute to most of our bodies' physiological processes. It has been determined that light is the major environmental cue that influences the setting of our circadian rhythm. Under ideal circumstances exposure to natural sunlight is sufficient to maintain a consistent and synchronized circadian rhythm. Often times this is not the case. Reduced exposure to natural light and increased exposure to artificial light are just two influencing factors.

Artificial light therapy has been successfully applied to the treatment of disorders of circadian rhythms as well as the treatment of some affective disorders. Most notably, light therapy has been shown to be effective in treating symptoms of depression and sleep disruption, specifically in patients with seasonal affective disorder, non-seasonal major depression, delayed sleep phase syndrome, advanced sleep phase syndrome, and sub-syndromal levels of each of these.

The theoretical mechanism of action is reviewed by Terman et al and asserts that morning bright light therapy advances and stabilizes the circadian rhythm of individuals who have delayed or drifting rhythms. There is subsequent synchronization and entrainment of the individual's endogenous rhythm with the environmental rhythm of daily life as reviewed in.

The timing, duration, and type of light delivered are of paramount concern, as improper delivery of therapy has been shown to have no advantage over placebo. One method of light delivery is simulated dawn light therapy. Simulated dawn light therapy works by gradually increasing light exposure over a specified period of time at the end of the sleep period. This gradually increasing light exposure during the sleep period is in contrast to traditional light therapy, which is delivered at full intensity after wake time. Simulated dawn has shown great promise as being just as effective as traditional light therapy but with the additional advantages of being more time efficient, easier to use, and more easily tolerated. All of these factors are important considerations in the application of this intervention to medical students, as being short on time and under significant stress are both hallmarks of medical education. The following proposal is a novel approach, using light therapy, to improve the mental well-being of first year medical students.