• anorexia nervosa
• autism spectrum disorder
• binge eating disorder
• borderline personality disorder
• bulimia nervosa
• catatonia
• feeding and eating disorders
• post-traumatic stress symptoms

Background: growing literature has recently focused on subthreshold autistic traits (AT), traumatic events and catatonic features among individuals with borderline personality disorder (BPD) and feeding and eating disorders (FED). It is known that autistic individuals are often exposed to traumatic events because of their difficulties in social cognition and in mentalization. Meanwhile, AT themselves as well as a story of traumatic events could represent vulnerability factors for the development of other psychiatric conditions, including eating disorders, mood disorders and catatonia. In this framework, the aim of this work is to analyse the presence of AT, catatonic and post traumatic symptoms among individuals with BPD and FED, as well as their reciprocal relationships.
Methods: 159 individuals (18 males and 141 females) were recruited from Psychiatric Clinic of Pisa. They were divided into three main diagnostic groups: BPD (n= 49), FED (n=55), healthy controls (HCs) (n=55). The FED group was divided into two other groups: the one made by individuals with Anorexia Nervosa (n=15), the other by subjects with Bulimia Nervosa or Binge Eating Disorder (BN/BED) (n=40). The Structured Clinical Interview for the fifth edition of diagnostic and statistical manual of mental disorders (DSM-5) (SCID-5) was employed for full-blown diagnosis of psychiatric disorders; additionally, in order to assess, according to a dimensional approach, various subthreshold and over threshold symptomatology, the following questionnaire were employed: the Adult Autism Subthreshold Spectrum (AdAS Spectrum), the Catatonia Spectrum (CS), and the Trauma and Loss Spectrum Self-Report (TALS-SR).
Results: our results showed a significantly higher score at the AdAS, CS and TALS-SR in both FED and BPD than healthy controls, except from the TALS-SR “Personal Characteristics and Risk Factors” domain in which BPD had higher scores than FED group, who, in turn, scored higher than HCs. We reported that AN individual significantly differed from BN/BED in the AdAS Non Verbal Communication and Child Adolescence domains and in the CS Automatism, Response to Instruction. Spearman correlation revealed a positive correlation between all AdAS domains and CS and TALS-SR domains. Meanwhile, all CS domains were correlated with TALS-SR ones. Multinomial regression analysis pointed out that both AdAS and CS total score were significant predictors for the inclusion in BPD or FED group. Specifically, AdAS Childhood Adolescence and Non verbal communication domains predicted the inclusion in both BPD or FED groups, with the first being slight more predictive of the inclusion in BPD group, while the second in FED group. About CS, Psychomotor activity predicted the inclusion in both BPD and FED groups, while Impulsivity only for inclusion in BPD one. Finally, linear regression pointed out that for the FED group, only AdAS symptoms predicted greater catatonic symptoms, while for the BPD one, both AdAS and TALS-SR were predictors of greater catatonic fetaures.
Conclusions: our findings indicate that both BPD and FED subjects exhibit more frequent AT, stress-related symptoms, and catatonic manifestations compared to controls, underscoring the complex interplay between neurodevelopmental vulnerabilities and psychiatric disorders. However, the two disorders seem to differ, each being associated with a specific pattern of autistic-catatonic features, while a closer association between personal characteristic of vulnerability and risk factors for trauma and stress related conditions seem to be associated with BPD. Moreover, our results support the hypothesis that BPD and FED may often be associated with the presence of AT, with potential pathways leading to the emergence of catatonic features. In particular, our results further confirm the predictive role of AT in the development of catatonia, while the predictive role of post-traumatic symptoms on catatonia in BPD, but not in FED, highlight the potential differences in the relationship between neurodevelopmental and environmental factors in the illness trajectories of these disorders.