Excessive daytime sleepiness, nocturnal sleep duration and psychopathology among Nigerian university students

Background and objectives. Short nocturnal sleep duration resulting in sleep debt may be a cause of excessive daytime sleepiness (EDS). Severity of depression (psychopathology) has been found to be directly related to EDS. There is an association between sleep duration and mental health, so there may therefore be an interrelationship between sleep duration, EDS and psychopathology. The objectives of this study were to determine the prevalence rates of EDS and general psychopathology among university students in Nigeria; determine the range of and mean sleep duration in the students; and determine the extent to which sleep duration and EDS predict general psychopathology in the same group of subjects. Materials and methods. Eight hundred and forty-five students at Obafemi Awolowo University, Ile-Ife, Nigeria, were recruited for the study. The subjects were required to provide information on their age, gender and the total amount of sleep per night they usually had. General psychopathology was assessed using the English language version of the 30-item General Health Questionnaire (GHQ-30). They were also evaluated for EDS using the English language version of the Epworth Sleepiness Scale (ESS). Results. Six hundred and thirty-four subjects (75.03% of the participants) provided complete data. The prevalence of EDS was 11.2% and the rate of general psychopathology in the subjects 13.1%. The range of sleep duration was 2 - 9 hours with a mean of 5.1 hours (standard deviation 1.3). On a regression model with the GHQ score as the dependent variable and sleep duration and ESS as the independent variables, the correlation coefficient between EDS, sleep duration and psychopathology (R) was 0.47. Conclusion. EDS and psychopathology are common in the student population studied. Nocturnal sleep duration for an average student is far less than that for an average adult. Nocturnal sleep duration and EDS acted as moderate predictors of general psychopathology among Nigerian university students. Volume 17 No. 4 December 2011 - SAJP