Factor Structure and Psychometric Properties of the <scp>BIS</scp> / <scp>BAS</scp> Scales in Children and Adolescents With Autism

The Behavioral Inhibition System and Behavioral Activation System (BIS/BAS) Scales offer a framework for assessing individual differences in sensitivity to reward and punishment-processes theorized to underlie key autism features. Despite widespread use, the psychometric properties of the BIS/BAS Scales have yet to be evaluated in the autistic population. Therefore, this study sought to evaluate the factor structure and psychometric properties of the BIS/BAS Scales in a sample of children and adolescents with autism. Parents of N = 709 autistic youth (M_age [SD] = 11.22 years [3.54]; 75% male) completed the BIS/BAS Scales alongside additional convergent/divergent validity measures. Factor structures ranging from one to eight specific factors were tested, including bifactor and hierarchical models with and without general factors. Measurement invariance was assessed across age groups (< 12 years vs. ≥ 12 years) and gender. Convergent and divergent validity were evaluated using bivariate correlations. Results indicated that a five-factor bifactor model-comprising general BIS and BAS dimensions alongside specific BIS-Fight/Flight/Freezing, BIS-Worry, BAS-Drive, BAS-Reward Responsiveness, and BAS-Fun Seeking factors-exhibited best fit and measurement invariance. Factors showed strong construct validity through correlations with emotion problems, risk avoidance, response inhibition, neuroticism, shyness, activity, and extraversion. Findings support the BIS/BAS Scales as a psychometrically sound measure of reward and punishment sensitivity in autistic youth. Further research is needed to confirm model generalizability, structural stability, and measurement invariance across both clinical and non-clinical populations.