The Sleep Condition Indicator: a clinical screening tool to evaluate insomnia disorder

TLDR

The study aims to develop and validate the Sleep Condition Indicator (SCI), a brief scale for assessing insomnia disorder in routine clinical settings. The SCI was evaluated in five samples comprising 30,941 participants, using web-based data collection to assess content validity, internal consistency, and concurrent validity with established sleep measures. The eight‑item SCI demonstrated strong internal consistency (α≥0.86) and convergent validity with the PSQI and ISI, and a two‑item short form correlated highly with the full scale (r=0.90), indicating its potential as a DSM‑5‑aligned insomnia screening tool.

Abstract

Objective Describe the development and psychometric validation of a brief scale (the Sleep Condition Indicator (SCI)) to evaluate insomnia disorder in everyday clinical practice. Design The SCI was evaluated across five study samples. Content validity, internal consistency and concurrent validity were investigated. Participants 30 941 individuals (71% female) completed the SCI along with other descriptive demographic and clinical information. Setting Data acquired on dedicated websites. Results The eight-item SCI (concerns about getting to sleep, remaining asleep, sleep quality, daytime personal functioning, daytime performance, duration of sleep problem, nights per week having a sleep problem and extent troubled by poor sleep) had robust internal consistency (α≥0.86) and showed convergent validity with the Pittsburgh Sleep Quality Index and Insomnia Severity Index. A two-item short-form (SCI-02: nights per week having a sleep problem, extent troubled by poor sleep), derived using linear regression modelling, correlated strongly with the SCI total score (r=0.90). Conclusions The SCI has potential as a clinical screening tool for appraising insomnia symptoms against Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria.