Pathogenic beliefs among patients with schizotypal personality disorder

This study aimed to explore the differences in pathogenic beliefs (PBs) between patients with schizotypal personality disorder (PD) and those with other PDs or without any PD. The study was conducted among 212 patients treated with psychotherapy at the Psychotherapy and Personality Disorder Clinic, Chiang Mai University between 2007 and 2019. Collected data included sociodemographic information, psychiatric disorders and personality disorder as determined by the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, 5(th) Edition, and the Pathogenic Belief Scale (PBS). An analysis was conducted to compare three groups, i.e., patients with schizotypal PD, patients with other PDs and patients without any PD. The PBS score was compared by two outcomes: a total score and a categorical score of individual items. The entire sample was predominantly female (62.3%) with a mean age of 31.41 years. Most participants had a bachelor's degree (76.9%), lived alone (72.6%) and received diagnoses of major depressive disorder (45.8%). No significant differences were found in participants' characteristics regarding age, sex, educational level, marital status and psychiatric clinical diagnosis among the three groups. The mean PBS total score was highest for schizotypal PD (mean = 58.74, SD = 11.54), compared with non-schizotypal PD (mean = 46.14, SD = 13.15) and non-PD (mean = 46.07, SD = 11.17). Twenty of 27 items were significantly higher in the schizotypal PD group than in other groups, after adjusting for type I error. The number of PBs was significantly prominent for schizotypal PD. Possible explanations were provided.