Temporal sleep patterns between healthy and depressed individuals

Background: Individuals with depression differ in their sleep patterns from healthy subjects. However, there are no studies that compare the temporal sleep patterns between healthy and depressed people or explore the relations between depressive symptomatology and physical activity levels. This study is an attempt to address this gap. Method: Participants recruited were 20 healthy and 20 depressed individuals. Data related to sleep-wake patterns, and activity levels were collected over four weeks using actigraph device (Actiwatch 2) and depressive symptoms were collected using the Depression Anxiety and Stress Scale (DASS) and Quick Inventory of Depressive Symptoms (QIDS) questionnaire. The data for the two groups were compared using t-tests. Correlation analyses were employed to test for associations between depressive symptoms, activity level and sleep patterns for each group. Result: The depressed group had significantly higher scores for depression, longer total sleep time, and lower level of activity compared to the healthy group. Sleep onset latency (SOL) was significantly correlated with the anxiety subscale of DASS, the depression score as measured by QIDS, and the activity level in the depressed group. The positive association between activity level and SOL was anomalous, and did not reflect the expected pattern seen in healthy individuals. Conclusion: The depressed group was confirmed to have significantly higher levels of depression, stress and anxiety, and lower level of physical activity. Increased anxiety and depression predicted delayed sleep onset. Depressive symptoms may have masked the expected relation between physical activity and SOL seen in healthy individuals.