Psychiatric aspects of shiftwork.

There is little rigorous evidence that shiftwork produces specific psychiatric disturbances. Substantial evidence suggests that shiftworkers are prone to increased drug and alcohol consumption, but the frequency with which this leads to actual drug abuse disorders has never been adequately defined. A preponderance of studies suggests that symptoms of a "neurotic" character are overrepresented among nightshift workers. The nature of these symptoms needs to be clarified with modern psychiatric nomenclature. It seems likely, based on certain experimental work, that nightshift work may at times exacerbate mood disorders, leading to an impression of "neurotic" disturbance. At the same time, some conditions of shiftwork might actually palliate mood disorders. Therefore, a reexamination of these issues is needed with improved research designs and more careful characterization of the nature of workers' complaints, their psychiatric histories (i.e., personal and family histories of mood disorders and other psychopathology), and possible specific effects of particular shiftwork rotation schedules. Use of bright light to alleviate mood disturbances associated with shiftwork needs extensive empirical testing.