Emotional functioning in boys with ADHD : identifying risk factors for comorbid Conduct Disorder

• Main Author: Northover, Clare
• Published: Cardiff University 2015
• Subjects: 618.92; BF Psychology
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681293

There is growing evidence that Attention Deficit Hyperactivity Disorder (ADHD) accompanied by Conduct Disorder (CD) is biologically as well as clinically distinctive. This subgroup shows greater symptom severity and poorer long-term prognosis than those with either CD or ADHD alone. The aim of the thesis is to build on existing neurobiological and emotional processing research and to identify mediators of risk for CD problems in ADHD, thereby highlighting targets for future intervention strategies. This thesis involved in-depth experimental testing of emotion processing and physiological responding to emotion-provoking stimuli in a large clinical sample of boys with ADHD (N=204). About half of the sample met diagnostic criteria for a comorbid diagnosis of CD enabling us to compare emotional and physiological responding between these two groups (ADHD vs. ADHD+CD). This large sample also enabled us to analyse the contributing effects of callous and unemotional traits, oppositional defiant disorder symptoms and internalizing emotionality, as well as looking at the effects of symptom severity of CD and ADHD. Each experimental chapter analysed responses to a different source of aversive cue. Pain sensitivity was assessed by looking at self-reported threshold and tolerance times and comparing these against increases in skin conductance level. Fear conditioning ability was analysed, looking at physiological responding to predict an aversive event. Stress reactivity was analysed by measuring emotional and cortisol responses to a psychosocial stressor and emotion regulation was assessed using an economic decision-making game. The findings showed that boys with ADHD and comorbid CD differed significantly in their emotional and physiological responding to those with ADHD alone. The boys with CD had more problems in learning fear associations, a weaker cortisol stress response, and a higher pain threshold and longer tolerance time, reflecting lowered pain sensitivity. Boys with high levels of aggressive CD symptoms also showed emotion regulation difficulties causing increased irrational decision making. This highlights the importance of treating ADHD as a heterogeneous condition and of analysing the effects of comorbid disorders to help ensure that limited resources in the healthcare, social care and criminal justice systems are utilised more effectively and efficiently.