The aim of this study was to investigate the neurochemical differences between borderline personality disorder (BPD) and antisocial personality disorder (ASPD) using proton magnetic resonance spectroscopy (¹H-MRS) in order to explore these disorders at a neurobiological level. In this cross-sectional study, 60 individuals with BPD and 60 individuals with ASPD participated. ¹H-MRS was performed using a Discovery MR 750 Magnetic Resonance Imaging (MRI) scanner with a 3.0 Tesla field strength to measure the levels of the metabolites GABA/Cr, N-acetylaspartate (NAA)/Cr, and glutamate (Glu)/Cr in the left anterior cingulate cortex (ACC) and the left orbitofrontal cortex (OFC) of the brain. The findings indicated that concentrations of GABA/Cr and Glu/Cr in the OFC were significantly higher in BPD patients compared to those with ASPD. In the ACC, GABA/Cr levels were elevated and NAA/Cr levels were reduced in the BPD group relative to the ASPD group. No significant differences were observed in Glu/Cr concentrations in the ACC or in NAA/Cr concentrations in the OFC. This study demonstrated significant neurochemical differences between BPD and ASPD in the ACC and OFC regions. These findings may enhance our understanding of the underlying neural mechanisms of these disorders and support the development of more targeted and effective therapeutic approaches.