Background

Eating disorders are amongst the deadliest of all mental disorders, however detection and early intervention rates remain extremely low. Current standardised screening questionnaires can be arduous or confronting and are ill-validated for online use, despite a universal shift to digital healthcare. The present study describes the development and pilot validation of a novel digital screening tool (the InsideOut Institute-Screener) for high risk and early stage eating disorders to drive early intervention and reduced morbidity.

Methods

We utilised a mixed cross-sectional and repeated measures longitudinal survey research design to assess symptom severity and recognised parameters of statistical validity. Participants were recruited through social media and traditional advertising, and through MTurk. An Eating Disorders Examination Questionnaire (EDE-Q) global score of 2.3 and assessment of eating disorder behaviours was used to determine probable ED. 1346 participants aged 14–74 (mean [SE] age 26.60 [11.14] years; 73.8% female, 22.6% male) completed the survey battery. 19% were randomised to two-week follow-up for reliability analysis.

Results

Strong positive correlations between the IOI-S and both the EDE-Q global (rs = .88) and SCOFF (rs = .75) total score were found, providing support for the concurrent validity of the scale. Inter-item correlations were moderate to strong (rs = .46–.73). Correlations between the IOI-S and two measures of social desirability diverged, providing support for the discriminant validity of the scale. The IOI-S demonstrated high internal consistency (α = .908, ω = .910) and excellent two-week test–retest reliability (.968, 95% CI 0.959–0.975; p ≤ 0.1). The IOI-S accurately distinguished probable eating disorders (sensitivity = 82.8%, specificity = 89.7% [AUC = .944], LR+  = 8.04, LR− = 0.19) and two stepped levels of risk.

Conclusions and relevance

The present study provides excellent initial support for the psychometric validity of the InsideOut Institute digital screening tool, which has the potential to streamline early intervention in the hopes of reducing current high morbidity and mortality. Further validation should be undertaken in known clinical populations.