Autism spectrum disorder among first-visit depressed adult patients: diagnostic clues from backgrounds and past history.

OBJECTIVE The present study aimed to extract discriminating indicators for diagnosis of autism spectrum disorder (ASD) from personal backgrounds and past history among depressed adult outpatients. METHODS Subjects were 430 depressed adults, consisting of patients with ASD (n=70) and those without ASD (n=360). Group comparison and discriminant analysis was conducted with regard to backgrounds (age, gender, education, marriage, living alone, physical diseases and family history of mood disorders) and past history (school non-attendance, bullied experience, psychotic-like experiences, conduct problems, suicide-related behaviors and interpersonal friction). RESULTS Six discriminating indicators (interpersonal friction, bullied experience, psychotic-like experiences, age under 32 years, school non-attendance and university educational level) were identified by stepwise discriminant analysis (P<.001). Absence of the first 4 indicators almost excluded ASD diagnosis with the highest negative predictive value (98%) and the least negative likelihood ratio (0.11) whereas one or more out of these 4 indicators showed low positive predictive value (32%) despite high sensitivity (93%). CONCLUSIONS The abovementioned 4 indicators may be useful clues to cover possible ASD subjects among depressed adults although further detailed ASD focused diagnostic procedure is absolutely necessary to specify true ASD subjects. Meanwhile, absence of these 4 indicators is probably helpful to rule out ASD diagnosis.