Does Atypical Lateralization Influence Comorbid Psychopathology in Children with Autism Spectrum Disorders?

People with autism spectrum disorder (ASD) often present with comorbid impairments. As over 70% of children with ASD meet the criteria for at least one comorbid psychiatric disorder, comorbidity is the rule rather than the exception. Some comorbid psychopathologies are especially prevalent, including schizophrenia, depression and attention deficit hyperactivity disorder (ADHD), begging the question of whether a common aetiology underlies their development. In comparison with the neurotypical population, the brains of people with ASD more frequently show atypically reduced or reversed hemispheric asymmetries for cognitive functions including language and face processing. Critically, atypical hemispheric asymmetries are also more common in schizophrenia, depression and ADHD than in the neurotypical population. This suggests that altered lateralization may play a role in predisposing not only the development of ASD but also its common comorbid psychopathologies, offering a potential account for their frequent coincidence. This paper thus reviews research examining hemispheric lateralization in children with ASD and comorbid psychopathologies to shed light on commonalities and differences in structural and functional lateralization. The research reviewed confirms a higher frequency of atypically reduced lateralization in all the disorders than in neurotypical populations, suggesting that a common genetic susceptibility may predispose alterations in hemispheric lateralization, resulting in the development of ASD and the common comorbidities. As such, atypical lateralization offers potential as a future diagnostic biomarker for ASD and concurrent psychopathologies. Research identifying the genes implicated in the loss of lateralization is vital to enable early identification and facilitate the early implementation of interventions and therapeutics.