Peripheral molecular markers of borderline personality disorder and modulation by psychotherapy

In borderline personality disorder (BPD), peripheral molecular markers may provide insights into the biological mechanisms underlying the disease, its clinical heterogeneity and treatment effects, while potentially offering clinical utility for patient stratification and prediction of response to therapies. Molecular systems related to social behaviour, pain processing and neural plasticity may contribute to different aspects of BPD and represent valuable targets for biomarker research.

This lecture will present findings from case-control and longitudinal studies investigating peripheral molecular markers related to these systems, with a focus on oxytocin (OXT), β-endorphin and BDNF, as well as on circulating microRNAs, which act as regulators of gene expression in these processes. Concerning OXT, the majority of studies point to lower peripheral levels in individuals with BPD compared with controls; moreover, altered OXT levels have been associated with emotional dysregulation, attachment-related difficulties and interpersonal disturbances. Preliminary results also suggests that psychotherapy may increase peripheral OXT concentrations. With regard to β-endorphin, evidence is very limited, with no differences found between BPD patients and controls; notably, lower baseline levels may predict treatment response, with increases observed in responders. For BDNF, case-control findings point to higher circulating levels in individuals with BPD, with preliminary evidence from our studies also suggesting associations with neuroimaging features, but no treatment-related modulation. Finally, our preliminary findings indicate differential expression of circulating microRNAs in BPD and changes in their expression during psychotherapy.

Overall, these data highlight the possible relevance of peripheral molecular markers in BPD and their potential clinical utility.