A new study examined the relationship between ADHD and oppositional defiant and conduct disorder, callous-unemotional traits, and reward-related inhibitory control.
According to recent research, about 50% of patients with attention-deficit/hyperactivity disorder (ADHD) also develop oppositional defiant and conduct disorder (ODD/CD).1 Additionally, callous-unemotional (CU) traits—including reduced guilt and remorse, callousness, low empathy, and deficient prosocial emotions—overlap with the dimensions of ADHD and ODD/CD symptoms.
One group of researchers sought to analyze whether reward-related inhibitory control (RRIC), approach motivation, and autonomic reactivity to reward-related stimuli are linked to developing ADHD, while keeping in consideration comorbid symptoms of ODD and CU traits.2
Researchers recruited a sample of 198 preschool children (115 boys, 83 girls) from child care facilities. The children were aged 4 to 5 years old at the first assessment, and 8 years old at the second assessment. Inclusion criteria include an IQ above 80; absence of motor or sensory disabilities and chronic physical and mental diseases; no indication of trauma; and no continuous pharmacological treatment. ADHD diagnosis was made by clinical interviews, and children with high ADHD symptoms were oversampled.
Researchers measured ODD symptoms and CU traits using a multi-informant approach. During the first assessment, RRIC was tested using the Snack-Delay task, or a test in which the child is instructed to wait for a ringing bell before they can take a treat that is covered by a transparent cup. During the second assessment, RRIC was tested using the Gift-Bag task, in which a red paper bag containing a gift for the child is placed on the table in front of them. The researcher then leaves the room for 5 minutes and instructs the child not to look while the experimenter goes to get their mother. For both tests, approach behavior was scored in accordance with the tests’ creator, Grazyna Kochanska, PhD.3
The results indicated a unique association between low RRIC and ADHD.
“We expected that RRIC deficits in ADHD can be explained by comorbid ODD symptoms. Contrary to this expectation, however, we found that the school-age ADHD diagnosis was significantly and uniquely associated with preschool- and school-age low RRIC. The associations could not be explained by comorbid ODD symptoms or CU traits,” the authors wrote.2
“High approach motivation indicated developing ADHD with ODD and CU problems, while low RRIC and low reward-related autonomic reactivity were linked to developing pure ADHD. The results are in line with models on neurocognitive subtypes in externalizing disorders,” concluded the authors.2
The study’s strengths included the consideration of neuropsychological and psychophysiological characteristics and psychopathological domains in a longitudinal design; the multi-informant approach (mother, father, teacher) to the assessment of comorbid symptoms; the use of dimensional scores reflecting the expression of comorbid symptoms; and the analysis of a sample with increased ADHD symptoms. A limitation was the lack of measurement of autonomic reactivity to neutral and negative stimuli.
“In future research, it would be interesting to assess further neuropsychological, biological and psychosocial characteristics and to analyze the role of ADHD symptom presentation (ie, inattention or hyperactivity/impulsive symptoms) in order to increasingly refine the characterization of the developmental pathways. Due to possible influences on our findings, the overlap between RRIC and the concept of delay aversion should be analyzed,” said the authors.2
1. Faraone SV, Asherson P, Banaschewski T, et al. Attention deficit/hyperactivity disorder. Nat Rev Dis Primers. 2015;1:15020.
2. Schloß S, Derz F, Schurek P, et al. Reward-related dysfunctions in children developing attention deficit hyperactivity disorder—roles of oppositional and callous-unemotional symptoms. Front Psychiatry. 2021;12:738368.
3. Kochanska G. Family Study. Effortful Control Batteries. University of Iowa; 2009.