Oxytocin, vasopressin, and their crosstalk in sexually-dimorphic psychiatric conditions.

This review looks at two brain chemicals (oxytocin and vasopressin) that might help explain why autism and anorexia, despite affecting different genders more often, sometimes occur together. Autism is more common in boys, anorexia in girls, but both involve social difficulties and eating issues. These brain chemicals affect social behavior and eating, and might work differently in males and females.

This review examines the role of oxytocin and vasopressin neuropeptides in autism spectrum disorder (ASD) and anorexia nervosa (AN), two conditions with opposite sex prevalence patterns but shared clinical features. ASD affects males 4:1, while AN affects females 10:1, yet both involve social difficulties, atypical eating, and reduced emotional awareness. The conditions co-occur 10 times more frequently than expected, suggesting shared mechanisms. The review explores how oxytocin and vasopressin, which regulate social behavior and feeding, may contribute to these disorders through sex-dependent pathways.

These peptides can interact with each other's receptors, producing both overlapping and opposing effects that may explain the paradoxical relationship between these conditions.

Clinicians should consider screening for anorexia nervosa symptoms in autistic females and autism traits in individuals with eating disorders. The shared neurobiological pathways involving oxytocin and vasopressin suggest potential for targeted interventions. Sex differences in presentation may require gender-specific assessment and treatment approaches.

This is a narrative review synthesizing existing evidence rather than presenting new empirical data. The abstract does not specify methodology, search strategy, or quality assessment criteria. No sample size or statistical analyses are reported as this is a theoretical review.

Autism spectrum disorder (ASD) and anorexia nervosa (AN) are prototypical neuropsychiatric conditions showing striking but opposite sex differences. ASD is about four times more prevalent in males, whereas AN occurs roughly ten times more often in females. Despite these contrasting ratios, both disorders share clinical features such as impairments in social behavior and cognition, atypical eating patterns, early onset, and reduced emotional awareness. Moreover, their comorbidity occurs about ten times more frequently than expected from general population rates, suggesting shared etiological factors that may act in opposite and sex-dependent directions.

Among potential mechanisms, the neuropeptides oxytocin and arginine vasopressin are implicated in both social and feeding behaviors and are central to sexual dimorphism. These peptides can also interact with each other's receptors, producing both overlapping and opposing effects. This review synthesizes current evidence on oxytocin and vasopressin in relation to social and feeding functions and their dysregulation in ASD and AN, aiming to explain the reason why these two disorders, despite their opposite sex ratios, frequently co-occur.