Orthorexic Tendencies Are Associated with Autistic Traits in Patients with Borderline Personality Disorder.

: Orthorexia Nervosa (ON), a condition marked by an obsessive focus on eating healthily, has drawn increasing clinical attention due to its rigid dietary patterns and social impairment. Borderline Personality Disorder (BPD), characterized by emotional dysregulation, impulsivity, and unstable interpersonal relationships, frequently co-occurs with eating disorders. Recent research suggests that autistic traits-such as cognitive rigidity and restricted interests-may underlie both ON and BPD, especially in female populations. This study aimed to assess the prevalence of orthorexic tendencies in patients with BPD compared to healthy controls (HCs) and to explore their associations with autistic traits and disordered eating behaviors. : This study involved 73 BPD patients and 52 HCs. Participants completed the Adult Autism Subthreshold (AdAS) Spectrum, Eating Disorder Inventory-2 (EDI-2), and the ORTO-15 questionnaire. : BPD patients scored significantly higher than HCs on AdAS Spectrum and EDI-2, and significantly lower on ORTO-15, indicating more pronounced autistic traits, disordered eating behavior, and orthorexic tendencies. A greater proportion of BPD individuals reported clinically relevant ON symptoms according to the ORTO-15 threshold. Orthorexic symptoms were significantly correlated with most EDI-2 and all AdAS Spectrum domains. Regression analysis revealed that autistic traits, but not feeding and eating disorder symptoms, significantly predicted orthorexic tendencies. : Orthorexic tendencies are more prevalent in individuals with BPD and are significantly associated with autistic traits. These findings suggest that ON may represent a manifestation of the autism spectrum, particularly in individuals with BPD, and support a reconceptualization of ON within a neurodevelopmental framework. : Future research is needed in order to clarify the temporal and causal relationships among autistic traits, BPD symptomatology, and the emergence of orthorexic behaviors.