Identifying the best sleep measure to screen clinical insomnia in a psychiatric population

Abstract

Background: Insomnia symptoms are highly prevalent among patients with psychiatric disorders, and this mandates the need to identify the best self-administered sleep measure to screen for clinical insomnia among them.

Methods: A total of 400 psychiatric outpatients completed the Pittsburgh Sleep Quality Index, Insomnia Severity Index (ISI), Epworth Sleepiness Scale, Flinders Fatigue Scale, Functional Outcomes of Sleep Questionnaire, and Dysfunctional Beliefs and Attitudes about Sleep Scale in a cross-sectional study. The sensitivity, specificity, positive, and negative predictive values of these six sleep scales were assessed and compared in relation to both ICD-10 and DSM-5 insomnia disorder status established using the interviewer-administered Brief Insomnia Questionnaire.

Results: Receiver operator characteristic curves with the area under the curve (AUC) revealed the ISI to be the most accurate measure to discriminate cases and non-cases on both ICD-10 (AUC = 0.88, 95% CI = 0.84-0.92) and DSM-5 (AUC = 0.82, 95% CI = 0.78-0.86) criteria with "good" accuracy. The cut-off scores of ≥14 and ≥ 11 for the ISI provided optimal sensitivity and specificity for the detection of ICD-10 and DSM-5 insomnia, respectively.

Discussion: With the new calling from DSM-5 to treat sleep symptoms in the presence of a co-existing mental condition, early detection of psychiatric patients with clinically significantly insomnia using a simple but accurate self-report sleep measure becomes important. Our study suggests that the ISI could be used as a potential screening tool for comorbid insomnia disorder in patients with mental disorders.

Keywords: Insomnia disorder; Insomnia severity index; Psychiatric population.