Elsevier

Sleep Medicine

Volume 8, Issue 3, April 2007, Pages 266-270
Sleep Medicine

Original article
Validity of the Pittsburgh Sleep Quality Index (PSQI) among Nigerian university students

https://doi.org/10.1016/j.sleep.2006.08.003Get rights and content

Abstract

Objectives

Sleep-related problems and detection of them remain largely an unidentified public health issue, especially among university students. This study aims to assess the validity of the Pittsburgh Sleep Quality Index (PSQI) among Nigerian university students.

Methods

Five hundred and twenty students completed the PSQI, the 12-item General Health Questionnaire (GHQ-12) and questionnaires pertaining to socio-demographic details. The students were then interviewed for the diagnosis of insomnia according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth edition (DSM-IV) and the International Classification of Sleep Disorders, revised criteria (ICSD-R).

Results

The PSQI was of moderate value in screening for insomnia, with the best cut-off score at 5 (sensitivity 0.720, specificity 0.545, overall correct classification rate 0.554). The correlation between the PSQI and the GHQ-12 was 0.252 (p < 0.001). A 3-factor model was generated by principal component analysis.

Conclusion

The psychometric value of PSQI in screening for insomnia among Nigerian students was moderate compared to what has been obtained in Western cultures. Nonetheless, it is still a useful instrument in the detection of sleep problems in this population.

Introduction

Sleep-related disorders are a major health issue. The estimated prevalence of sleep problems in the general population range between 15% and 24%, and prevalence as high as 62% has been reported in the elderly population [1]. Poor sleep quality has been associated with increased tension, irritability, depression, confusion and generally lower life satisfaction [2]. Students have been identified as a population group particularly affected by problems with sleep [3], [4], [5]. A majority of university students are in late adolescence and early adulthood, and, due to the stress of education and the academic workload, their sleep patterns and related problems could differ from non-students their age [6].

The extent of sleep-related problems among Nigerian university students is unknown. In a developing country like Nigeria, where there is inadequate personnel to assess sleep problems in students, a rating scale would be an invaluable tool to estimate sleep-related problems in this population. The most widely used sleep instrument is the Pittsburgh Sleep Quality Index (PSQI). The PSQI [7], introduced in 1989, has acquired extensive acceptance as a useful instrument in measuring sleep quality in diverse groups of patients. The questionnaire is easy to understand and can be completed in 5 min or less. It has been shown to have good validity for patients with psychiatric and sleep disorders [8] and for patients with other somatic diseases [9]. It has also been used among student populations [10].

Although the PSQI had been widely validated in various cultures and populations, searches of literature revealed no validation or use of the instrument in sub-Saharan Africa. The aim of this study was to assess the validity and usefulness of the PSQI among Nigerian university students.

Section snippets

Sample population

The study population consisted of students of the Obafemi Awolowo University, lle-lfe, a federal university in south-western Nigeria, which offers both undergraduate and postgraduate degrees. The university has 10 faculty members and a student population of about 30,000 students from virtually all ethnic groups, tribes and religions in the country.

A multi-stage, stratified sampling technique was used to recruit students for the study. Students were approached by faculty members, and 60 students

Socio-demographic and sleep-related data

Out of the 600 participants contacted, 52 refused participation and 28 had incomplete data, so only a total of 520 questionnaires were analyzed. The mean age of the participants in years was 23.24 (standard deviation (SD) 3.16). There were 318 (61.2%) males. A majority of the participants were Christian (85.4%), and 451 (87.1%) were from the Yoruba ethnic group. The mean number of years spent in school was 3.76 (SD 2.16). The average wake-up time in Greenwich Mean Time (GMT) was 5.06 (SD 1.00),

Discussion

To our knowledge, this study is the first to examine the usefulness of a sleep screening instrument among university students in sub-Saharan Africa. The main finding from our study was differences in mean subcomponents scores of the PSQI compared to findings in the Western and non-Western cultures [8], [9], [15]. This may suggest that the quality of sleep differs among cultures or it may suggest that different cultures have a different perception of sleep and its problems. Since the PSQI was

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