Overlap of autistic and schizotypal traits in adolescents with Autism Spectrum Disorders

This study addresses the unraveling of the relationship between autism spectrum and schizophrenia spectrum traits in a population of adolescents with Autism Spectrum Disorders (ASD). Recent studies comparing isolated symptoms of both spectrum disorders as well as diagnostic criteria for each (DSM-IV-TR) suggest resemblances in the clinical phenotype. A group of 27 adolescents with ASD (11 to 18 years) and 30 typically developing adolescents, matched for age and gender, participated in this study. Within the ASD group 11 adolescents satisfied DSM-IV-TR criteria for schizotypal personality disorders. Autistic and schizotypal traits were identified by means of well validated questionnaires (Autism Questionnaire, AQ and Schizotypal Personality Questionnaire-Revised, SPQ). Significantly more schizotypal traits in adolescents with ASD were found than in typically developing controls. Besides high levels of negative symptoms, adolescents with ASD also displayed high levels of positive and disorganized symptoms. There appeared to be a relationship between the mean level of autistic symptoms and schizotypal traits, as well as specific associations between autistic symptoms and negative, disorganized and positive schizotypal symptoms within individuals. Schizotypal symptomatology in all sub dimensions that are reflected by the SPQ scores, was most prominently associated with attention switching problems of the autism symptoms from the AQ. These findings indicate that patients diagnosed with an ASD show schizophrenia spectrum traits in adolescence. Although other studies have provided empirical support for this overlap in diagnostic criteria between both spectrum disorders, the present findings add to the literature that behavioral overlap is not limited to negative schizotypal symptoms, but extends to disorganized and positive symptoms as well.