31,32 In the late 1970s, various attempts were made to provide more operational guidelines for autism33,34 and the condition was officially recognized for the first time in DSM-III.6 Inclusion of infantile autism as an explicitly defined category was a major accomplishment. Unfortunately the DSM-III definition proved overly narrow (indeed focusing on the “infantile” form of the disorder), was “monothetic” (ie, every single feature/criterion

Inhibitors,research,lifescience,medical had to be present) and thus was overly stringent. In DSM-III developmental change was dealt with by including a category for “residual” infantile autism.5 This problem was addressed in the Inhibitors,research,lifescience,medical revision of DSM-III that appeared in 1987.35 The DSM-III-R

definition was DNA Damage inhibitor polythetic, with combinations of multiple criteria in the three traditional areas of disturbance (social, communication, behavior) with highly detailed criteria (some of which included examples). This definition owed a considerable intellectual debt to Lorna Wing’s work, focused on a broader spectrum concept of autism and related conditions.36 A field trial was conducted but proved problematic in some respects.37-39 Inhibitors,research,lifescience,medical It appeared that the criteria provided favored overdiagnosis of autism in more cognitively impaired individuals (where high rates of stereotyped behaviors are frequent) and a relative underdiagnosis in more cognitively Inhibitors,research,lifescience,medical able groups. Another potential problem included the potential for major differences with the changes to be made in ICD-10 then scheduled to appear at about

the same time as the new DSM-IV. Given the concern that for autism, two competing diagnostic approaches would impact research some consideration was made for a joint effort to derive a diagnostic approach suitable for both publications. In the diagnosis of autism spectrum Inhibitors,research,lifescience,medical disorders (ASDs), both DSM-IV and ICD-10 adopt an explicit categorical approach, and although the systems differ in some respects for autism the definitions are virtually identical based on the results of a large international field trial.40 The field trial included 21 sites with over 100 raters providing information on nearly 1000 cases who were included in the field trial if autism oxyclozanide was being considered in the differential diagnosis. The sample exhibited a range of ages (from young children to adults), levels of functioning (from those who had severe cognitive impairments to gifted individuals), and symptom severity. Based on a series of preliminary data reanalysis it was agreed that the system developed for autism should aim to have a reasonable balance of sensitivity and specificity across the IQ and age ranges and a convergence, at least for autism and related conditions, between DSM-IV and ICD-10 if at all possible.