Borderline personality disorder (BPD) is a severe mental disorder characterized by marked emotional instability, impulsivity, difficulties in interpersonal relationships, and disturbances in identity. Although it has traditionally been studied mainly in adults, there is increasing evidence that symptoms may already appear during adolescence.

A study led by the Psychiatry, Mental Health and Addictions Group at the Vall d’Hebron Research Institute (VHIR), in collaboration with FIDMAG Germanes Hospitalàries Research Foundation, provides new insights into the neurobiological basis of the disorder in early stages using neuroimaging studies. Both groups collaborate regularly and are part of the Mental Health area of the Biomedical Research Networking Center (CIBERSAM) of the Carlos III Health Institute (ISCIII).

The studies, published in Neuropsychobiology, Journal of Psychiatric Research, Psychological Medicine and Translational Psychiatry, use advanced structural and functional neuroimaging techniques to examine the brains of adolescents diagnosed with BPD.

“The aim is to understand what happens in the brain during the early stages of the disorder,” explains Marc Ferrer, psychiatrist at Vall d’Hebron University Hospital and principal investigator of the project. “Studying adolescents allows us to analyze the disorder at a stage where there are fewer confounding factors, such as long disease duration or pharmacological treatments.”

Studying the brain in the early stages of the disorder

The studies include samples of adolescents diagnosed with BPD and healthy age-matched control groups. In some of the works, most participants with BPD had not received pharmacological treatment and had no other associated psychiatric disorders, allowing for a more precise analysis of brain changes potentially linked to the disorder.

FIDMAG’s advanced neuroimaging design integrates multiple modalities of structural and functional MRI (fMRI), enabling a comprehensive characterization of brain alterations. Researchers analyzed both the volume of different brain regions and their activity during cognitive tasks related to executive function, autobiographical memory, and social cognition.

One study based on brain morphometry identified reduced gray matter volume in the left temporoparietal region, an area involved in understanding others’ mental states and perspective-taking. These differences persisted even when analyzing only unmedicated participants without comorbidities, suggesting a direct association with the disorder.

Other studies examined brain activity during neurocognitive tasks thought to engage regions involved in identity and social cognition, core aspects in new diagnostic models for personality disorders.

Results showed alterations in activation and deactivation of the Default Mode Network, as well as in the dorsolateral prefrontal cortex, a key area for inhibitory control and emotional regulation.

According to the researchers, these regions belong to brain networks involved in fundamental social processes, such as interpreting others’ intentions or constructing personal identity. Their disruption, together with emotional dysregulation, may be linked to the functional impairment seen in patients with BPD.

Dr. Pilar Salgado-Pineda, researcher at FIDMAG Germanes Hospitalàries, emphasizes that “magnetic resonance imaging is a key tool that allows safe, non-invasive exploration of the brain in mental disorders. Identifying brain functioning patterns associated with BPD helps pinpoint the most involved regions and opens the door to personalized medicine approaches.”

“Many of the core symptoms of BPD relate to difficulties in emotional regulation and in how individuals construct their identity and interpret relationships with others,” explains Marc Ferrer. “The alterations observed in these brain networks may help explain these phenomena from a neurobiological perspective.”

A longitudinal research line

These studies are part of a broader research line that follows the same participants over time to analyze how brain changes evolve and how they relate to the clinical course of the disorder.

According to José Antonio Ramos-Quiroga, head of the Psychiatry Service at Vall d’Hebron University Hospital and leader of the VHIR Psychiatry, Mental Health and Addictions group, this type of research is essential for advancing understanding of mental disorders. “Neuroimaging allows us to begin identifying the brain circuits involved in different psychiatric disorders,” he explains. “In the long term, this may help develop more precise and personalized diagnostic and treatment strategies.”

Researchers highlight the need for larger samples and long-term follow-up studies, but note that these findings support the idea that BPD has identifiable neurobiological bases already during adolescence.

Overall, this research line contributes to a better understanding of the brain mechanisms involved in the development of BPD and may open new avenues for identifying early markers of the disorder, ultimately facilitating earlier detection and intervention.

The project was funded by the ‘Health Research Projects’ grant from the Carlos III Health Institute. Project title: ‘Borderline Personality Disorder with adolescent onset: study of structural and functional neurobiological alterations’ (PI15/02025). Principal investigator: Dr. Marc Ferrer Vinardell.