Diagnosis of autism spectrum disorder: reconciling the syndrome, its diverse origins, and variation in expression.

Recent discoveries about the pathogenesis and symptom structure of autism spectrum disorders (ASDs) are challenging traditional nosology and driving efforts to reconceptualise the diagnosis of autism, a goal made all the more pressing by new prospects for early identification, targeted intervention, and personalised-medicine approaches to specific autistic syndromes. Recognition that ASD represents the severe end of a continuous distribution of social communication abilities in the general population has stimulated attempts to standardise the measurement of autistic traits and to set appropriate clinical thresholds for diagnosis. Over the next decade, rapid advances in our understanding of symptom structure and the diversity of causes of ASD could be incorporated into the next evolution in the diagnosis of autism, with important implications for research, clinical practice, public health, and policy. As differential effects of personalised therapies are identified in relation to specific causes of autism, the benefits of an updated diagnostic nosology will translate into the delivery of more effective care for patients.