Motor activity and perception of sleep in depressed patients

Subjectively experienced sleep patterns often differ from observed sleeping behavior in insomniacs. Sleep patterns have been evaluated by measurements of motor activity in healthy subjects and insomniacs, but results may depend on the insomnia subtype. Sleep disturbances are frequent complaints in depression, but the influence of psychopathology on activity measurements remains elusive. Therefore, the relationship between reported sleep complaints and motor activity was studied in patients with major depression. Severity of depression was documented in depressed inpatients by observer-(HAMD) and self-rated scales (DACL, SHAPS-D). Self-reports of sleep were obtained by Pittsburgh Sleep Quality Index (PSQI) and daily sleep logs (DSL). Motor activity was continuously recorded over 72 h by actigraphy. 'Good' sleepers showed less motor activity during the night compared to 'poor' sleepers (p<0.01). Patients with high HAMD scores (> or = 18) showed greater nocturnal motor activity and less sleep quality compared to patients with low HAMD scores (p<0.01). When controlling for age and severity of depression, partial correlation was found to be significant between perceived daily sleep quality and nocturnal motor activity (r = -0.63, p<0.01). There was a significant effect of nocturnal motor activity as a covariate on disturbances of subjective sleep quality and severity of depression as the main effect (p<0.01). In depressed patients, nocturnal motor activity seems to be an indicator of experienced sleep disturbances. The results warrant further controlled studies to evaluate the role of psychological factors for objective measurements and subjective perception of sleep patterns.