Academic journal article South African Journal of Psychiatry

Excessive Daytime Sleepiness, Nocturnal Sleep Duration and Psychopathology among Nigerian University Students

Academic journal article South African Journal of Psychiatry

Excessive Daytime Sleepiness, Nocturnal Sleep Duration and Psychopathology among Nigerian University Students

Article excerpt

The average adult human sleeps for about 8 of every 24 hours. (1) Most of our sleep occurs at night, since we function predominantly during the day and it is necessary to be awake and alert. Under certain conditions, humans are unable to maintain the state of wakefulness needed for daytime functioning. Excessive daytime sleepiness (EDS) manifests with increased sleepiness in situations in which the individual would reasonably be expected to be awake and alert.

Common causes of EDS include sleep deprivation, (2) obstructive sleep apnoea, narcolepsy, idiopathic hypersomnia and sedative/ hypnotic drugs. (3) Obstructive sleep apnoea is characterised by snoring and episodes of apnoeic attacks during sleep. Narcolepsy is characterised by excessive daytime sleepiness, cataplexy (sudden decrease or loss of muscle tone often precipitated by intense emotion), sleep paralysis and hypnagogic (sleep-onset) hallucinations. The features of idiopathic hypersomnia include chronic sleepiness without cataplexy or other features of narcolepsy.

Short total nocturnal hours of sleep and depression are among the known risk factors for daytime sleepiness. (4) Total sleep time has an inverse relationship with excessive daytime sleepiness. (4) On the other hand, the severity of depression (psychopathology) has been found to be directly related to EDS. (5-8)

Many factors account for total nocturnal sleep duration. It has been found that older age, depression, coffee intake, especially at night, and excessive Internet use at night are significantly associated with short nocturnal sleep duration. (9) Short nocturnal sleep duration has been found to reduce cognitive and behavioural functioning (10) and to be associated with poor health status. (11) Short sleep duration also increases the risk of motor vehicle accidents. (12) It would therefore appear that both daytime sleepiness and sleep duration are important variables contributing to neurocognitive and behavioural functioning, health status (including mental health), and public safety risks.

Information on the possible relationship between excessive daytime sleepiness, sleep duration and general psychopathology in Nigeria is generally inadequate. The present study aimed to provide information in this regard, with respect to university students. The study aimed to determine the extent to which nocturnal sleep duration and EDS act as predictors of general psychopathology among Nigerian university students, the prevalence rates of EDS and general psychopathology, and the range of and mean nocturnal sleep duration in the study subjects.

Materials and methods

Study setting and ethical considerations

The proposal for this study was approved by the Ethics and Research Committee of the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. The participants were undergraduates of Obafemi Awolowo University, Ile-Ife. Written informed consent was obtained from all who took part in the study. It was a cross-sectional study.


A total of 845 students were recruited into the study. Obafemi Awolowo University has 13 faculties and a student population of about 25 000. Sixty-five students were recruited from each faculty through a multi-stage, stratified sampling technique, aiming for a total of 845 students.


The General Health Questionnaire is a widely used screening instrument. It detects a wide range of psychological disorders and therefore gives a measure of current mental health. It was developed by Goldberg as a screening instrument to identify psychological distress in primary care settings (13) and has been extensively used and shown to be a valid and reliable instrument across cultures. (14-21) The questionnaire was initially developed as a 60-item instrument but there are a wide range of shortened versions including the GHQ-30, the GHQ-28, the GHQ-20 and the GHQ-12. …

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