Dual diagnosis, defined in this instance as the co-occurrence of mental health disorders with mental retardation, has become a major area of clinical practice and research in the past 10 years. Whereas areas such as differential diagnosis, assessment, and prevalence have been major focuses of research, etiologies of dual diagnosis have received less attention. Current etiological theories have practical implications for the treatment and prevention of dual diagnoses and suggest important directions for future research. This article provides a historical review of theory development in the field of dual diagnosis. Current status of etiological theories and future directions are discussed with an aim toward encouraging further study.

Reliability and validity of three commonly used autism scales, the Autism Behavior Checklist (Krug, Arick, & Almond, 1980), the Real Life Rating Scale (Freeman, Ritvo, Yokota, & Ritvo, 1986), and the Childhood Autism Rating Scale (Schopler, Reichler, & Renner, 1988), were investigated. Data analyses were based on completed protocols for 24 children or adolescents who met DSM-III-R criteria for pervasive developmental disorders. First, to replicate previous findings, interrater reliability of each of the two direct observational scales was assessed. Second, correlations between pairs of the three scales were calculated. Third, diagnostic classifications based on autism scale cutoff scores were compared to classifications based on DSM-III-R criteria. Fourth, relationships between autism scale scores and adaptive behavior scores were investigated. Results and implications for the use of these scales in the assessment of autistic behaviors are discussed.

Three children with autism and mental retardation were treated for deficits in self-initiated speech. A novel treatment package employing visual cue fading was compared with a graduated time-delay procedure previously shown to be effective for increasing self-initiated language. Both treatments included training multiple self-initiated verbalizations using multiple therapists and settings. Both treatments were effective, with no differences in measures of acquisition of target phrases, maintenance of behavioral gains, acquisition with additional therapists and settings, and social validity.

This article describes attempts by an inpatient unit, treating adolescents with developmental delays and with severe psychiatric disturbances, to reduce its use of physical restraints. This restraint reduction process involved two phases: (1) assessment and (2) systems intervention. The assessment phase consisted of extensive observations of staff response to patient crises, staff interviews, patient interviews, and the development of a data-tracking system for restraint and seclusion (R/S) usage. Multiple contributing factors were identified during the assessment phase that increased R/S usage. The second phase, organizational and clinical intervention, included staff education and training, treatment interventions, and system changes aimed at reducing R/S usage. R/S reduction data over the course of the project are presented.

A time delay procedure was used to increase spontaneous verbalizations of 3 autistic children. Multiple baseline across behaviors designs were used with target responses, selected via a social validation procedure, of two spontaneous responses ("please" and "thank you") and one verbally prompted response ("you're welcome"). The results indicate gains across target behaviors for all children, with occurrence across other stimuli and settings. These gains were validated socially with 10 adults. Furthermore, increases in appropriate language had no effect on levels of inappropriate speech.