Assessing the psychometric properties of two food addiction scales.

BACKGROUND: While food addiction is well accepted in popular culture and mainstream media, its scientific validity as an addictive behavior is still under investigation. This study evaluated the reliability and validity of the Yale Food Addiction Scale and Modified Yale Food Addiction Scale using data from two community-based convenience samples.

METHODS: We assessed the internal and test-retest reliability of the Yale Food Addiction Scale and Modified Yale Food Addiction Scale, and estimated the sensitivity and negative predictive value of the Modified Yale Food Addiction Scale using the Yale Food Addiction Scale as the benchmark. We calculated Cronbach's alphas and 95% confidence intervals (CIs) for internal reliability and Cohen's Kappa coefficients and 95% CIs for test-retest reliability.

RESULTS: Internal consistency (n=232) was marginal to good, ranging from α=0.63 to 0.84. The test-retest reliability (n=45) for food addiction diagnosis was substantial, with Kappa=0.73 (95% CI, 0.48-0.88) (Yale Food Addiction Scale) and 0.79 (95% CI, 0.66-1.00) (Modified Yale Food Addiction Scale). Sensitivity and negative predictive value for classifying food addiction status were excellent: compared to the Yale Food Addiction Scale, the Modified Yale Food Addiction Scale's sensitivity was 92.3% (95% CI, 64%-99.8%), and the negative predictive value was 99.5% (95% CI, 97.5%-100%).

CONCLUSIONS: Our analyses suggest that the Modified Yale Food Addiction Scale may be an appropriate substitute for the Yale Food Addiction Scale when a brief measure is needed, and support the continued use of both scales to investigate food addiction.