The internship year: a study of sleep, mood states, and psychophysiologic parameters.

Previous reports have suggested that first-year graduate physicians have a high incidence of psychologic distress and may show cognitive impairment as a result of sleep deprivation. We periodically evaluated 27 interns during their training year to determine amount of sleep, mood states, reaction time, critical flicker fusion, and symptoms of depression. We found the incidence of major depression in our subjects (four of 27) to be lower than previously reported but higher than expected for that age group in the general population. Risk factors for depression during the internship year were history of major depression, female sex, and unmarried status. The only significant change in average mood state was that anger progressively increased during the year. Subjects slept an average of 5.95 hours per 24-hour day during the year. Correlational analysis indicated that, contrary to predictions, performance on reaction time and critical flicker fusion improved with less sleep. At the end of the year, subjects regarded the year as stressful but not more so than had been anticipated.