Motor activity and daily variation of symptom intensity in depressed patients.

Spontaneous motor activity measured by actigraphy and subjectively experienced intensity of symptoms were investigated in 16 unipolar depressed inpatients with melancholic features. Patients felt significantly less active, awake, and more depressed in the morning compared to the evening. However, morning activity levels appeared significantly higher compared to evening levels. Diurnal variations of symptoms were reflected by actigraphically measured motor activity, which was negatively correlated with subjectively experienced symptom intensity. Increased motor activity may represent an observable, psychobiological, behavioral equivalent of self-experienced depressive symptoms in major depression with melancholic features.