Facial muscle electromyography in depressed and nondepressed hospitalized subjects: a partial replication.

Imagining happy events, sad events, and the events of a typical day led to measurable electromyographic (EMG) changes in the corrugator muscle of the face in both depressed and nondepressed subjects. The depressed and nondepressed subjects could not be differentiated on the basis of muscle activity, whether depression was defined by a self-rating scale, an adjective checklist, or research criteria. Previous investigators have observed differences in the facial EMG patterns of depressed and nondepressed subjects who were not hospitalized; the authors suggest that such changes are a consequence of a general psychological stress state rather than of depression specifically.