How should applied psychologists conceptualise an autism spectrum disorder diagnosis and its predictive validity?

Aim: Many educational and clinical psychologists are involved in autism diagnosis services, yet there is no clarity about the nature of the disorder underlying what they believe they are diagnosing. This paper therefore aims to examine some typical assumptions about the implications of an autism spectrum disorder (ASD) diagnosis. Rationale: This conceptual review questions whether ASD represents a distinct kind of disorder, in view of the substantial changes in definitions of autism over the past 50 years. This is addressed from the perspective of philosophy of science by considering whether ASD constitutes a natural kind with explanatory and predictive value. Findings: Research studies have failed to identify any distinct cognitive abnormality which uniquely characterises autism. There are no interventions specifically for people with an ASD diagnosis which, when available, are not also effective for those with other conditions. Outcomes for those with the diagnosis may be more varied than hitherto supposed and may depend on other variables apart from the diagnosis itself. Limitations: It is impossible to cover all relevant research for a fully comprehensive overview of the field in a paper of this length. However, most of the research and review papers cited are of recent date. Conclusions: It is difficult to see ASD as a distinct natural kind of psychological disorder. The outlook for those diagnosed is often hard to predict. Psychologists therefore need to be cautious about the manner in which they communicate diagnoses to avoid overly gloomy prognostications. [ABSTRACT FROM AUTHOR]