(PS11-B31) The Effects of ADHD Symptom Severity and Emotional Dysregulation on Internalizing and Externalizing Comorbidities in Children with and Without ADHD

Purpose: ADHD is highly comorbid with many internalizing and externalizing disorders, including mood disorders, anxiety disorders, and ODD. However, the mechanisms underlying why some children with ADHD have comorbidities and some do not is uncertain. One possible mechanism is the severity of ADHD symptoms. An additional feature of ADHD that may be related to comorbidity is emotional dysregulation, a transdiagnostic mechanism that is characterized by disproportionately extreme and labile emotions. While severe ADHD symptoms and emotional dysregulation are both common in children with ADHD, their relationship to comorbidity in ADHD remains unclear. Procedure: The present study used a cross-sectional design to examine the estimative effects of ADHD symptom severity and emotional dysregulation on internalizing and externalizing comorbidities in children with and without ADHD. A total of 212 participants ages 7-12 (ADHD=127, no ADHD=85; Male=125, Female=87; Caucasian/White=69.8%, Black/African-American=19.3%, Other=10.5%) completed the study. Parents of children completed the DISC to assess for ADHD and for internalizing and externalizing disorders, the Vanderbilt Assessment Scale to measure ADHD symptom severity, and the PANAS negative affect scale through a 3x day/7 day Ecological Momentary Assessment (EMA) protocol to assess emotional dysregulation. Mean Square Successive Difference was used for data reduction for EMA data. Results: Hierarchical logistic regression estimated the likelihood of concurrent internalizing and externalizing disorders for children with and without ADHD. Covariates (age, race, sex) and ADHD diagnosis were entered in step 1, inattentive and hyperactive/impulsive symptom severity was entered in step 2, and EMA-derived emotional dysregulation was entered in step 3. For internalizing disorders, EMA-derived emotional dysregulation was associated with a 5.4% increase in the likelihood of concurrent internalizing disorders for each unit increase in EMA MSSD (Wald=6.05, p=.05); no other variable or step was significant. For externalizing disorders, children with ADHD were 8.68 times more likely to have a comorbid externalizing disorder (Wald=28.73, p< .001). Inattentive symptom severity was associated with a 13% increase in odds of a comorbid externalizing disorder for each unit increase (Wald=5.32, p< .05), while EMA-derived emotional dysregulation was associated with an 11% increase in odds of a comorbid externalizing disorder for each unit increase (Wald=12.77, p< .001). Conclusions: These findings suggest that internalizing comorbidities in children with and without ADHD are a function of emotional dysregulation and not ADHD symptom severity, while externalizing comorbidities in children with and without ADHD are a function of both. Future research directions and limitations are discussed.