A Study on Correlation between Severity of Depression and Quality of Sleep

Objective: To study the correlation between severity of depression and the quality of sleep disturbances in patients with non psychotic depression. Method: A cross-sectional study of a cohort of 30 outpatient sample with non psychotic depression were recruited for the study. Controls were the accompanying relatives of the patients. Study was conducted at a government hospital in Tamil Nadu, South India. Inclusion criteria in the study group required fulfillment of ICD 10 criteria for major depressive disorder. Patients who were 18yrs of age and above and both male and female genders were included in the study. Both study and control groups were administered the Pittsburg Sleep Quality Index (PSQI) and the Epworth sleepiness scale to measure the quality of sleep disturbances in the sample. Correlation between HAMD depression severity and the PSQI sleep quality scores and the Epworth sleepiness scale scores in the depressive patients and the correlation between nocturnal sleep disturbances and day-time sleepiness among depressed patients were analyzed using Pearson correlation coefficient.  Results: Analysis revealed significant inverse correlation between the severity of depression and components of quality of sleep such as subjective sleep quality, total sleep duration and habitual sleep efficiency and positive correlation with sleep latency. Conclusions: Study shows that as the severity of depression increases the severity of sleep disturbances also increases which also was significant when compared with the various components of sleep quality on the PSQI scale.