Comorbid symptom severity in attention-deficit/hyperactivity disorder: a clinical study

Abstract

Objective: Although current attention-deficit/hyperactivity disorder (ADHD) diagnostic criteria do not include emotional symptoms, externalizing behavior problems, or aggression, the practicing clinician is often faced with the evaluation and management of these symptoms when assessing and treating patients with ADHD. While much research has focused on comorbid disorders in ADHD, less attention has been directed to comorbid symptoms that may or may not meet syndrome criteria but that influence ADHD treatment planning and outcome. The aim of this study is to describe emotional and behavioral symptoms in children and adolescents with ADHD and compare them with non-ADHD control groups.

Method: From 1995 to 2005, clinically referred children and adolescents with the combined subtype of ADHD (n = 175) or the inattentive subtype of ADHD (n = 70) as diagnosed by the primary physician (using DSM-IV criteria) were compared with a non-ADHD psychiatric control group (n = 65) and a non-ADHD community control group (n = 72) on measures that assessed emotional symptoms, externalizing behavior problems, and aggression; comparisons were controlled for age, sex, and family income.

Results: Both ADHD groups had depressive symptom severity equal to a non-ADHD psychiatric control group and greater than community control groups. Externalizing behavior problems and aggression were more severe in the ADHD combined subtype group compared with other groups. As ADHD symptom severity increased, externalizing behavior problems and aggression, but not internalizing symptoms, also increased in severity. Family income had an independent relationship with externalizing disorders.

Conclusions: High rates of internalizing emotional symptoms, externalizing problem behaviors, and aggression were found in a clinical ADHD sample. Externalizing behavior problems and aggression appeared to be related to the hyperactive-impulsive ADHD symptom domain and to overall ADHD symptom severity. It remains an empirical question as to whether effective treatment of the core symptoms of ADHD will also reduce the presence of associated emotional and behavioral symptoms and improve daily functioning in children and adolescents with ADHD.