Empirically derived subtypes of pervasive developmental disorders: a cluster analytic study.

A cluster analytic study was conducted to empirically derive behaviorally homogeneous subtypes of pervasive developmental disorders (PDD). Subjects were clustered based on a broad range of behavioral symptoms which characterize autism. Behavioral variables were measured using several of the standardized psychometric instruments most commonly employed in assessing autistic individuals. The cluster solution indicated the presence of four distinct groups. Validity checks generally confirmed significant between-group differences on independent measures of social, language, and stereotyped behaviors. In addition, the four-group cluster solution was compared to previously developed typological systems of PDD (i.e., subcategories based on IQ early onset, styles of social interaction, and DSM-III-R diagnosis). Results generally supported both the behavioral homogeneity of the four subgroups and also several important between-group differences. The potential utility of using cluster analyses to explore subtypes of PDD is discussed.

Comparison of psychotic and autistic children using behavioral observation.

The purpose of this study was to assess the relationship between autism and childhood psychosis. Fifteen children with psychotic symptoms were compared to 15 children with autism, using two observational measures, the Ritvo-Freeman Real Life Rating Scale (RLRS) and the Childhood Autism Rating Scale (CARS), which rate subjects on behaviors pathognomic to autism. In comparison to autistic persons, psychotic individuals were judged to have better language and social skills. In addition, autistic persons were also rated as having more difficulty adapting to new situations and appeared more "autistic-like." Overall scores on the CARS and RLRS were significantly different between the two groups, indicating that these two assessment instruments may be useful in differential diagnosis. However, 20% of the psychotic subjects received pervasive developmental disorder diagnoses, indicating that there may be a relationship between those two disorders.

Empirical study of mental health professionals' knowledge and attitudes towards the concept of age appropriateness.

Questionnaires on age appropriateness were completed by 100 mental health professionals from 10 states. In general, the respondents were familiar with the concept and had learned about age appropriateness from a variety of sources. Age appropriateness was defined in terms of chronological age rather than mental age or the two concepts combined. Respondents viewed it as a particularly important component in treatment success, especially in working with people who have developmental disabilities, adolescents, and young adults. Implications of these findings and suggestions for future research were provided.

A 4-year follow-up of treatment of self-injury.

Data on the long-term effectiveness of behavioral treatment for self-injurious behavior in individuals with mental retardation is rare. We present 4-year follow-up data on a 28-year-old man whose severe self-injurious behavior was treated with brief contingent electric stimulation via the Self-Injurious Behavior Inhibiting System (SIBIS). Event data collected throughout follow-up showed reductions in head-hitting and head-banging from over 2,600 responses per hour to approximately 1 response per hour during much of the first 31 months of treatment. However, the rate of head-banging began increasing thereafter, with the SIBIS losing its effectiveness to such an extent that it was no longer clinically useful.