Recent developments in neuropsychological models of childhood psychiatric disorders

The number of studies on the neuropsychology of childhood disorders has increased exponentially over the past decade. We report the results of an initial meta-analysis of key neuropsychological constructs included in studies of nine of the most prevalent childhood disorders. Results indicated that the neuropsychological etiologies of each of these disorders are complex and multifactorial. No single deficit is necessary or sufficient to explain all cases of any disorder, but preliminary evidence suggests that disorders may be distinguished by profiles across multiple neuropsychological processes. Slow processing speed and increased response variability are ubiquitous across disorders, but somewhat distinct profiles emerge on different aspects of executive functions. Attention deficit/hyperactivity disorder and Tourette's disorder are most strongly associated with inhibitory difficulties, whereas difficulties with cognitive flexibility are most pronounced in groups with autism spectrum disorders and childhood-onset schizophrenia. Working memory difficulties are significant in most groups, but these weaknesses are largest in groups with learning disorders and childhood-onset schizophrenia. Future research is needed to clarify further the relations among these heterogeneous diagnostic phenotypes and complex neuropsychological processes to facilitate studies that link these weaknesses to specific etiological risk factors.