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

Area of Science:

• Psychiatry
• Sleep Medicine
• Clinical Psychology

Background:

• Insomnia disorder is a prevalent condition requiring effective clinical assessment tools.
• Existing measures may not be suitable for rapid evaluation in routine practice.

Purpose of the Study:

• To develop and psychometrically validate the Sleep Condition Indicator (SCI), a brief scale for evaluating insomnia disorder.
• To assess the SCI's utility in everyday clinical practice.

Main Methods:

• The SCI was developed and evaluated across five diverse study samples.
• Psychometric properties including content validity, internal consistency, and concurrent validity were investigated.
• Data were collected from 30,941 individuals via dedicated websites.

Main Results:

• The eight-item SCI demonstrated robust internal consistency (α≥0.86).
• The SCI showed convergent validity with established instruments like the Pittsburgh Sleep Quality Index and Insomnia Severity Index.
• A two-item short-form (SCI-02) strongly correlated with the full SCI score (r=0.90).

Conclusions:

• The Sleep Condition Indicator (SCI) shows promise as a clinical screening tool for insomnia.
• The SCI facilitates the appraisal of insomnia symptoms against DSM-5 criteria.
• The brief nature and strong psychometric properties support its use in clinical practice.