Independent and Interactive Associations of Encopresis and Attention-Deficit/Hyperactivity Disorder in Children on Emotional–Behavioral Symptoms, Executive Functioning, and Avoidant/Restrictive Food Intake–Related Symptoms

In this multicenter, cross-sectional case–control study, we examined the independent and interactive associations of encopresis and attention-deficit/hyperactivity disorder (ADHD) with emotional-behavioral symptoms, executive functioning, and avoidant/restrictive food intake-related symptoms in children. The sample included 148 children aged 5–10 years assigned to four groups: healthy controls (n = 31), ADHD-only (n = 60), encopresis-only (n = 31), and encopresis plus ADHD (n = 26). Diagnoses were established using clinician-administered semi-structured interviews, and parent-report measures assessed emotional-behavioral symptoms, executive functioning, and eating-related symptoms. Across analyses, impairment followed a graded pattern, with the encopresis plus ADHD group showing the highest level of impairment (H = 89.84, p < 0.001). Emotional symptoms and internalizing problems were most pronounced in the encopresis-only and comorbid groups (p < 0.001). Fear-based eating behaviors were significantly elevated in the comorbid group (H = 25.00, p < 0.001). Executive functioning impairments also followed a graded pattern, with the greatest dysfunction in the comorbid group (p < 0.001). After additional adjustment for Clinical Global Impression-Severity, encopresis × ADHD interaction effects remained significant for emotional symptoms (β = 3.227, p = 0.011) and fear-based eating (β = 3.196, p = 0.033). Children with co-occurring encopresis and ADHD showed the most severe cross-sectional clinical profile, highlighting the importance of assessing emotional symptoms, executive functioning, and fear-based eating in this subgroup.