Running head: ASPERGER S AND SCHIZOID 1. A New Measure to Differentiate the Autism Spectrum from Schizoid Personality Disorder

Transcription

1 Running head: ASPERGER S AND SCHIZOID 1 A New Measure to Differentiate the Autism Spectrum from Schizoid Personality Disorder Peter D. Marle, Camille S. Rhoades, and Frederick L. Coolidge University of Colorado at Colorado Springs Patricia L. Monaghan Nova Southeastern University

2 ASPERGER S AND SCHIZOID 2 A New Measure to Differentiate the Autism Spectrum from Schizoid Personality Disorder The purpose of this paper was to present the preliminary psychometric qualia of a new measure designed to differentiate between syndromes in the autistic spectrum (e.g., Autistic Disorder, Asperger s Disorder, and High Functioning Autism) from schizoid personality disorder traits. The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR; American Psychiatric Association, 2000) notes that the differential diagnosis for the autism spectrum, specifically Asperger s Disorder, from the schizoid personality disorder is problematic as the relationship between those two disorders is unclear (p. 83). Thus, a measure which would differentiate the autism spectrum from schizoid personality disorder might be of diagnostic value. The essential problem in their differential diagnosis is that the qualitative impairments in social interactions and the restricted patterns of behavior, interests, and activities overlap considerably, despite the clinical suspicions that people with schizoid personality disorder prefer or choose to be alone, whereas people with Asperger s Disorder are suspected to have an underlying neurological impairment that results in their aloneness. In a previous study, Thede and Coolidge (2006) sampled the extant literature on the autism spectrum symptomatology and created a 44-item survey that was specifically designed to differentiate the symptoms of Asperger s Disorder from the symptoms of High Functioning Autism. This survey was shown to have high internal reliability (Cronbach s α =.98; N = 88) and excellent test-retest reliability (r =.93), however, it could not differentiate between children with Asperger s Disorder and children diagnosed with High Functioning Autism. It did significantly differentiate between those two groups of children and a control group of children without those diagnoses and no presenting clinical diagnosis. Monaghan (2010) also surveyed

3 ASPERGER S AND SCHIZOID 3 the autism literature and added an additional item to the original 44-item survey, and then attempted to differentiate children who were classified as loners by their parents from children who were diagnosed by a mental health professional with Asperger s Disorder. The present study is a reanalysis of Monaghan s initial study with additional participants in both the Asperger s Disorder group and a control group of children not diagnosed with Asperger s Disorder and who were not classified as loners by their parents. Method Participants in the present study were 43 boys and 30 girls ranging in age from 3 to 16 years old (M = 8.9 years, SD = 4.2 years). The parents of these participants were recruited from friends and families of students enrolled in psychology courses at a midwestern university. An initial demographic survey assessed whether the children in the study had been diagnosed with Asperger s Disorder by a mental health professional (PhD, MD, or PsyD) and a group of children whose parents considered them loners. The final sample of N = 73 consisted of 19 children diagnosed by a mental health professional with Asperger s Disorder, 19 children who were considered loners by their parents but had never been diagnosed as having autism, and 35 children in a control group who had never warranted any psychological diagnosis according to parental reports. This study was conducted with the approval of the University s Institutional Review Board. The measures used in this study included the new 45-item scale, the Coolidge Autistic Symptoms Survey (CASS), a 200-item scale, the Coolidge Personality and Neuropsychological Inventory for Children (CPNI), which contains scales measuring 12 childhood personality disorder traits, informed consent, and a demographic form. Packets were hand-delivered or mailed to parents. The CASS items were answered on a 1 (Hardly Ever or Never) to 4

4 ASPERGER S AND SCHIZOID 4 (Frequently) scale, and the sum across the 45 items served as the dependent variable in subsequent CASS analyses. The CASS items covered four general classes of symptoms: socialization, speech and language, nonverbal communication, and repetitive/stereotyped behavior. Results The CASS internal scale reliability (Cronbach s α) was excellent (α =.97; N = 73). The CASS test-retest reliability (one week) was also high (r =.91; N = 45). A principal components analysis (with various varimax rotations) revealed that a one-component solution appeared to best fit the data, eigenvalue = 22.1, total variance accounted for = 49.1%. A one-factor ANOVA was conducted upon CASS sum among the three groups, Asperger s, loners, and control, and it was significant, F(2, 70) = 69.0, p <.001. A Tukey s post hoc analysis determined that the control group (M = 59.7, SD = 9.6) scored significantly lower than the loner group (M = 92.9, SD = 28.4), which in turn scored significantly lower than the Asperger s group (M = 118.8, SD = 17.2). There was a large effect size (partial η 2 =.66). A one-factor ANOVA was also conducted upon the sum of the 7-item Schizoid Personality Disorder scale of the CPNI among the three groups, and it was also significant, F(2, 70) = 21.9, p <.001. A Tukey s post hoc analysis revealed that the CPNI was able to distinguish the control group (M = 10.9, SD = 2.7) from the loner group (M = 16.6, SD = 3.7) and the Asperger s group (M = 16.1, SD = 4.4). The latter two groups, however, were not significantly different. It is interesting to note that the loner group had 13 of 19 children score at least one standard deviation above the normative mean on the Schizoid Personality Disorder scale. Discussion

5 ASPERGER S AND SCHIZOID 5 Preliminarily, it appears that the CASS may be a useful measure in order to differentiate between children with Asperger s Disorder and children who may have a high probability of having schizoid personality disorder traits. It also appears that the CASS is imminently successful at differentiating nonclinical children from those with Asperger s Disorder. Certainly, further research is warranted.