Self-Regulation of Emotion, Functional Impairment, and Comorbidity Among ChildrenWith AD/HD.

Children with AD/HD are at increased risk for experiencing serious, lifelong impairments in multiple domains of daily functioning (Barkley, 2006). Such impairments are intensified in the presence of comorbid conditions, which occur in up to 60% of clinic-referred children with AD/HD (August, Realmuto, MacDonald, & Nugent, 1996). Oppositional-defiant disorder (ODD) is a particularly common comorbid condition, which, left unchecked, can lead to more serious behavioral complications, most notably conduct disorder (CD; Angold, Costello, & Erkanli, 1999; Cunningham & Boyle, 2002; Jensen, Martin, & Cantwell, 1997). In addition to being predisposed to co-occurring externalizing difficulties, children with AD/HD are at increased risk for displaying comorbid internalizing problems. For example, in both epidemiological and clinical studies, children with AD/HD have been shown to be at 20% to 30% increased risk for developing depression (Biederman, Mick, & Faraone, 1998). Similar findings have been reported for anxiety disorders, with up to 25% of the child AD/HD population displaying one or more anxiety conditions (Tannock, 2000). Meta-analytic studies lend further support to these findings, suggesting that the odds of having AD/HD and comorbid depression range from 3.5 to 8.4, with an overall median odds ratio of 5.5 (Angold et al., 1999). Elevated but slightly lower odds ratios have also been reported for AD/HD and anxiety disorders, ranging from 2.1 to 4.3, with a median of 3.0 (Angold et al., 1999). Although the association between AD/HD and internalizing disorders is well established, the processes or mechanisms by which this association occurs have yet to be identified. One commonly held assumption is that having AD/HD places a child at risk for repeated experiences of failure and frustration across the home, school, and social domains, thereby setting the stage for internalizing disorders to occur (Patterson & Capaldi, 1990). Unfortunately, research addressing this possible developmental pathway from primary AD/HD symptoms—inattention, impulsivity, hyperactivity—to secondary internalizing psychopathology has been lacking. Thus, questions remain as to how comorbid depression, anxiety, and other internalizing disorders arise. Another possible explanation for this clinical phenomenon stems from a consideration of what actually constitutes the core features of AD/HD. Inattention, impulsivity, and hyperactivity have long been recognized as primary symptoms of this disorder. Along with these cognitive and behavioral manifestations, it is possible that difficulties regulating emotions are another central feature of AD/HD and that being emotionally labile confers increased risk for experiencing functional impairment and comorbid internalizing problems. Clinical accounts of children with AD/HD are certainly compatible with this possibility. In particular, parents, teachers, and clinicians commonly describe such children as having higher emotional highs and lower emotional lows. Moreover, such children seem more prone to react emotionally to everyday situations and to have greater difficulty regulating their emotions as they are occurring. In support of these clinical descriptions are recent theoretical accounts that ascribe a more central role to the self-regulation of emotion in the presentation of AD/HD (Barkley, 2006; Nigg, 2001). In Barkley’s (2006) model, for example, self-regulation of affect is defined as the process by which an individual’s capacity for inhibition allows them to delay responding to events that elicit emotional responses, especially those of a negative nature (e.g., anger). The greater the capacity for delay, the more likely it is that an individual can gather information necessary for understanding an emotionally charged event. This in turn affords an individual greater opportunity for modifying or moderating an emotional response earlier to its public display. Although limited in number, studies have found evidence of an association between AD/HD and deficits in the self-regulation of affect or emotion. One of the earliest articles addressing this matter was reported by Douglas (1988), who observed that children with AD/HD became overly aroused and excited in response to rewards and more frustrated when rewards were withdrawn and less available. Subsequent research has also shown that children with AD/HD display higher rates of negative affect (e.g., anger, sadness), greater emotional reactivity, and lower levels of empathy relative to normal controls (Braaten & Rosen, 2000; Cole, Zahn-Waxler, & Smith, 1994; Hinshaw & Melnick, 1995; Jensen & Rosen, 2004; Maedgen & Carlson, 2000; Martel, 2009; Melnick & Hinshaw, 2000; Walcott & Landau, 2004). Together, such findings lend support to the notion that deficits in the self-regulation of emotion exist among children with AD/HD (Skirrow, McLoughlin, Kuntsi, & Asherson, 2009). Remaining less clear, however, is the clinical significance of these emotional findings and how specific they are to AD/HD. For example, it has not yet been established whether deficits in the self-regulation of emotion are evident in all children with AD/HD or perhaps only in a subgroup of children with this disorder. Also unclear is whether deficits in the self-regulation of emotion increase the risk for functional impairment or for comorbid conditions, especially those of an emotional nature. Finally, in light of findings suggesting that a small percentage of children with AD/HD may display comorbid bipolar disorder (BD; Biederman et al., 1996), it is also necessary to consider the possibility that comorbid BD, rather than AD/HD, accounts for these emotion regulation difficulties. The current study examined these issues in the context of a larger-scale investigation of AD/HD among 5- to 12-year-old probands and their siblings. Consistent with the fact that children with AD/HD display different combinations and intensities of inattention, impulsivity, and hyperactivity (e.g., AD/HD subtypes), our expectation was that a substantial number of probands and siblings with AD/HD, but not all, would display evidence of a deficit in the self-regulation of emotion and that these deficits would exist independent of the presence of BD. It was also predicted that, for those children affected by AD/HD, deficits in the self-regulation of emotion would moderate outcomes and be associated with greater functional impairment, as well as with increased levels of comorbid features. Given the heterogeneity of the population, AD/HD subtyping was also expected to play a role, with higher levels of impairment and comorbid features anticipated among those with the combined (C) subtype versus those with either the predominantly inattentive (I) or predominantly hyperactive-impulsive (HI) subtypes. As further evidence of this increased risk for impairment and comorbidity, we expected increased rates of treatment service utilization among those with an impaired capacity for regulating emotions.