Prodromal and autistic symptoms in schizotypal personality disorder and 22q11.2 deletion syndrome.

Despite clear diagnostic distinctions, schizophrenia and autism share symptoms on several dimensions. Recent research has suggested the two disorders overlap in etiology, particularly with respect to inherited and noninherited genetic factors. Studying the relationship between psychotic-like and autistic-like symptoms in risk groups such as 22q11 deletion syndrome (22q11DS) and schizotypal personality disorder (SPD) has the potential to shed light on such etiologic factors; thus, the current study examined prodromal symptoms and autistic features in samples of 22q11DS and SPD subjects using standardized diagnostic measures, including the Structured Interview for Prodromal Symptoms (SIPS) and the Autism Diagnostic Inventory-Revised (ADI-R). Results showed that SPD subjects manifested significantly more severe childhood and current social as well as stereotypic autistic features, as well as more severe positive prodromal symptoms. The two groups did not differ on negative, disorganized, or general prodromal symptoms, but were distinguishable based on correlations between prodromal and autistic features; the relationships between childhood autistic features and current prodromal symptoms were stronger for the SPD group. The results suggest that childhood autistic features are less continuous with subsequent prodromal signs in 22q11DS patients relative to those with SPD, and the findings highlight the importance of studying the overlap in diagnostic phenomenology in groups at risk for developing psychosis and/or autism.