Neuropsychiatric differences among adolescents with early and late onset conduct, and externalizing and internalizing disorders presenting to a specialist service

Abstract

Objective: The two papers presented investigate whether disorders in childhood are distinctive in their etiology and development and then extends to broader domains of child and adolescent mental disorders. The first paper focuses on psychiatric illness, neuropsychological and psychosocial dysfunction within the domain of externalizing disorders, examining differences between early and late onset conduct disordered (CD) youth. The second paper examines differences in neuropsychological and psychosocial function between externalizing and internalizing youth. Method: Paper one compares the psychiatric, neuropsychological and psychosocial function of 43 subjects with either childhood-onset or adolescent-onset CD. Paper two examines the neuropsychological and psychosocial function of 148 subjects across the two domains of externalizing and internalizing disorders. Participants were compared with normative scores from control samples in each study. Results: The first study shows differences between childhood-onset and adolescent onset CD youth for verbal learning and memory function, psychosis, childhood maltreatment and violent behavior with childhood onset youth performing worse on these measures. Both childhood and adolescent onset CD youth were impaired in executive function. The second study found significant differences between the externalizing disordered youth and both the internalizing and comorbid youth on executive function, with the externalizing youth exhibiting severe impairment in this area or cognitive function. Conclusion: Childhood onset CD is associated with more severe cognitive impairment, more psychiatric symptoms and childhood adversity than adolescent-onset youth. They were also more likely to commit serious, violent offences. When CD youth were included in a larger externalizing sample and compared with internalizing and comorbid youth, distinctiveness between the domains remained for some cognitive functions, specifically executive function