Programmatic Research into Co-Occurring Psychiatric Syndromes in Autism Spectrum Disorder

Background: People with autism spectrum disorder (ASD) commonly experience the symptoms of a wide range of non-ASD psychiatric syndromes, which raises a number of questions about diagnosis and treatment and has important implications for models of pathogenesis. Do seeming psychiatric syndromes meet conventional criteria for diagnostic validity?  To what extent are psychiatric syndromes in ASD similar to or different from disorders diagnosed in typically developing (TD) individuals? Do the core deficits associated with ASD alter the clinical presentation of traditionally-defined syndromes? Are psychiatric syndromes in ASD associated with the same clinical correlates (risk factors) as similar syndromes in TD populations. Is the assessment of co-occurring symptoms clinically informative? 

Objectives: For the past 20 years our research team has addressed these and related questions in children and adolescents referred for clinical evaluation of ASD and non-ASD psychiatric syndromes as well as community-based TD samples. This presentation summarizes the results of these studies and suggests directions for future research.

Methods: Parents and teachers completed a DSM-IV-referenced rating scale with established psychometric properties in several thousand children and adolescents (ages 3-18 years) with ASD, psychiatric referrals, and public school children. The parents of the referred children also completed an extensive background questionnaire that included a range of psychosocial variables commonly used in epidemiologic and case-control studies, and subsamples of these youth are currently participating in genetic and imaging studies 

Results: Co-occurring psychiatric symptoms in ASD appear to meet conventional criteria for diagnostic validity, share many similarities with conventional DSM-defined syndromes, result in relatively high levels of symptom-induced impairment, are associated the important real-world outcomes, and evidence similar biopsychosocial clinical features (risk factors) as comparable syndromes in TD populations. Nevertheless, findings from studies comparing ASD and TD samples also evidence group differences therefore challenging conventional ideas about nosology 

Conclusions:  

Evidence for the existence of behavioral syndromes within the ASD clinical phenotype is compelling. Moving forward, future studies will need to address not only diagnostic heterogeneity within ASD (e.g., HFA, males) and heterogeneity in co-morbidities (e.g., anxiety) but also heterogeneity within co-morbid symptoms (e.g., social anxiety) and heterogeneity in etiological pathways (e.g., stress, cytokines). The incorporation of neuroscience into traditional, behaviorally-oriented research strategies for addressing the real-world service needs of people with ASD holds considerable promise for answering some of the more vexing questions about diagnosis and nosology and is essential in examining pathogenic processes, developmental trajectory, and response to intervention.