Neurocognitive Dysfunction in Children and Adolescents with Mental Illness

Abstract

Introduction Robust evidence from adult samples indicates that neurocognitive dysfunction is a hallmark of many mental illnesses, contributing to the loss of daily function and quality of life that these illnesses cause. However, it is still unclear whether neurocognitive deficits associated with mental illnesses begin to manifest well before adulthood. The current study addresses this gap by evaluating neurocognitive function in four groups of children and adolescents with different mental illnesses compared to their matched healthy peers. Methods We evaluated the neurocognitive performance of four samples of youth diagnosed with ADHD (N=343), Anorexia (N=40), First-onset psychosis (N=25), and Conversion Disorder (N=56) with age-matched healthy controls. Performance was assessed using an objective assessment battery designed for use across diagnoses and settings and validated for its correlations with underlying brain structure and function. The resulting analyses assessed accuracy and reaction time performance for neurocognitive domains well established in the adult literature, such as cognitive flexibility, executive function, response inhibition, verbal fluency, verbal memory, visual memory, sustained attention, and working memory. Clinical and healthy group performance was compared using non-parametric testing. Results Distinct profiles of neurocognitive dysfunction were detected for each diagnosis. Particularly, children and adolescents with ADHD diffusely performed worse than their healthy counterparts, with exceptional impairment in working memory. Children and adolescents with anorexia displayed more specific impairments limited to response inhibition and verbal memory. While youth with ADHD had the most cognitive domains affected, youth with first-onset psychosis displayed the most severe impairments compared to healthy controls. Finally, deficits in conversion disorder were limited to cognitive flexibility, executive function, decision making, response inhibition, and working memory. These findings suggest that neurocognitive impairment in mental illness is transdiagnostic and can be detected as early as childhood or adolescence with standardized computerized testing.