There is growing evidence that Borderline Personality Disorder (BPD) and eating disorders (EDs) share common genetic and neurobiological vulnerabilities. Both disorders are frequently associated with neuroticism, impulsivity, and emotion dysregulation.

One shared risk factor involves variants of the serotonin transporter gene (5‑HTTLPR). The short allele, in particular, is prevalent in individuals with BPD and in those with bulimia nervosa or binge eating disorder (Steiger, 2004; Ni et al., 2009). These gene variants influence serotonergic function, which affects behavioral traits such as mood regulation, appetite control, and impulse management.

This overlap suggests that BPD and EDs may exist along a shared neurobiological spectrum, shaped by both genetic predisposition and environmental experiences (e.g., trauma, early adversity).