2 Neuroscience2.11 Integrated neurobiology of syndromes and states
2.11.18 Neurobiology of personality disorders
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Written by Resident Doctor Committee · Published
New in the 2027 syllabus
The College added this topic for exams from January 2027.
Developmental and circuit models
Personality disorder means long-lasting difficulties with a person's sense of self and with their relationships. Its neurobiology varies from person to person. It develops as inherited and environmental influences act on each other.
Temperament. Traits such as sensitivity to threat and impulsivity can increase vulnerability. They do not decide which diagnosis, if any, develops.
Early adversity may affect how a person regulates stress and how they learn. It is neither necessary nor sufficient for every personality disorder.
Process studied | Candidate systems | Limit on interpretation |
|---|---|---|
Emotional reactivity | Amygdala, insula and salience networks | Responses vary with the task and the person's current state |
Regulation and impulse control | Prefrontal and anterior cingulate networks | Differences are not specific to one disorder |
Interpersonal prediction | Mentalising networks (making sense of mental states) and social learning networks | Behaviour also depends on relationships and experience |
Stress response | Hypothalamic-pituitary-adrenal (HPA) and autonomic systems | Medication, trauma and comorbidity affect the measurements |
Using findings carefully
Borderline personality disorder. Studies report differences in emotional and interpersonal processing, but affected and unaffected groups overlap a great deal.
Group differences cannot give a brain signature that diagnoses the disorder. Nor can they explain the cause of one person's behaviour.
Cross-sectional findings come from one point in time. They may reflect vulnerability, distress, adaptation or treatment exposure. Longitudinal and experimental studies answer different questions.
Plasticity. Learned expectations and ways of regulating emotion can change. This fits with people improving through psychological treatment.
Clinical formulation brings together biological vulnerability, learning, relationships and present circumstances. Do not use neuroimaging to conclude that a person's character is fixed and cannot change.