Excessive Daytime Sleepiness in Schizophrenia: A Naturalistic Clinical Study

Excessive Daytime Sleepiness (EDS) and sleep problems are common in patients with schizophrenia. The symptom of EDS in schizophrenia can be attributed to various causes including neurobiological changes, sleep disorders, medication or as a symptom of schizophrenia itself. EDS as a symptom in schizophrenia has been understudied.

To assess the prevalence of EDS and to the study the same in patients with first episode and chronic schizophrenia.

In this cross-sectional study 100 patients suffering from schizophrenia as per International Classification of Diseases (ICD-10) criteria were evaluated for sleep quality using the Pittsburgh Sleep Quality Index (PSQI) and EDS using the Epworth Sleepiness Scale (ESS). The severity of illness was assessed by Positive and Negative Symptom Scale for Schizophrenia (PANSS) while cognition was assessed using the Frontal Assessment Battery (FAB) and the Trail Making Test A and B. The data was statistically analysed.

A total of 100 patients (72 male and 28 female) aged 18 to 64years (mean age 30.63 years) were studied. Poor sleep quality (PSQI > 6) was exhibited by 83% of patients. Excessive daytime sleepiness (ESS > 7) was found in 32% of patients. There was no statistically significant difference in various parameters according to the age, duration of illness or gender. However, first episode patients differed in having better sleep quality than patients with chronic schizophrenia (p=0.0002). Cognition was not affected by sleep quality.

A high prevalence of sleepiness and poor sleep quality was noted in the entire sample but it did not have any correlation with age and gender. It also did not affect the cognitive test scores. Further research in this area is warranted.