Comorbidity aggregation models in children and adolescents with ADHD and direct and moderator effects of familial clinical history and psychosocial factors

: ADHD condition occurs with an extensive variety of comorbid mental disorders This study aims to individuate models of comorbidity aggregation in 1086 probands with ADHD and the direct and moderator effect of First Degree Relatives (FDRs) Mental Disorders and socio-environmental factors. Principal Component Analysis individuated four models of highly related comorbidities in affected probands. Inter-psychiatric and inter-neurodevelopmental comorbidities associations, with higher loading of Anxiety-Depressive-Conduct and "Intellectual-Language-Motor" subgroups of disorders were distinctly collocated within first and second components respectively. Regression and moderator analyses highlighted the effect of familiarity ADHD among siblings and socio-environmental factors in both components; in addition, FDRs psychiatric disorders worked as direct factors in the first component. Tic-Tourette and Autism vs. Bipolar Disorder and Intellectual Disabilities; Opposition-Conduct vs. Learning Disabilities subgroups in the third and fourth components, respectively, defined contraposed comorbidity profiles. Mothers with ADHD moderated by lower rates of ADHD siblings; high negative parenting and lower FDRs neurodevelopmental disorders represented the direct effect for the third and fourth components, respectively. Proband's age as well as disorders loading within more components contribute to better define these comorbidities subgroups. The findings suggest to consider a nosology of ADHD that takes in account of comorbidity profiles and their co-related familial and environmental risk factors.