What is Borderline Personality Disorder (BPD)?

BPD is a personality disorder characterised by pervasive instability in affect, self-image, interpersonal relationships and behaviour. Symptoms typically begin in adolescence or early adulthood and can cause substantial distress and impairment—but with appropriate treatment many people improve markedly.

Core symptoms & diagnostic features

• Intense, rapidly shifting emotions (affective instability)
• Unstable interpersonal relationships — idealisation followed by devaluation
• Marked impulsivity (spending, substance use, risky sex, binge eating)
• Chronic feelings of emptiness and unstable self-image/identity
• Frantic efforts to avoid real or imagined abandonment
• Recurrent suicidal behaviour, gestures, threats, or self-harm
• Stress-related paranoid ideation or dissociation

Diagnosis is clinical and based on a pattern of behaviour across contexts, not single incidents.

Common presentations / subtypes (clinical patterns)

While DSM does not mandate subtypes, clinicians often recognise presentation patterns which help tailor treatment:

• Emotionally unstable / high-affect (classic): marked mood swings, self-harm, crisis-prone.
• Impulsive / acting-out: prominent impulsivity, substance misuse, risky behaviours.
• Discouraged / depressive style: withdrawal, chronic emptiness, dependent features.
• Angry / externalising: irritability, aggression, frequent conflict with services or family.

Why BPD develops — contributing factors

• Genetic and temperamental vulnerability (high emotional reactivity)
• Early attachment disruption, childhood adversity or trauma
• Invalidating environments that shape emotion regulation difficulties
• Neurobiological differences in emotion and impulse regulation

Assessment — what to evaluate

1. Detailed clinical interview and developmental history.
2. Assess suicidal ideation, intent, past attempts and self-harm behaviours.
3. Screen for comorbidities: mood disorders, PTSD, substance use, eating disorders.
4. Functional impact: work, relationships, self-care, legal issues.
5. Risk formulation and safety planning — immediate priority if active risk.
6. Use structured tools as needed (e.g., MSI-BPD, SCID-5-PD) to support diagnostic clarity.

Evidence-based treatments

Psychotherapy is the cornerstone of BPD treatment. There are several well-supported models; choice depends on availability and patient preference.

1. Dialectical Behavior Therapy (DBT)

• Strongest evidence for reducing self-harm, suicidal behaviour and hospitalisations.
• Skills training modules: emotion regulation, distress tolerance, interpersonal effectiveness, mindfulness.
• Combines individual therapy, group skills training, phone coaching and consultation teams for therapists.

2. Mentalization-Based Therapy (MBT)

• Focuses on improving mentalizing — understanding self and others’ mental states.
• Reduces interpersonal crises and improves affect regulation.

3. Schema Therapy

• Targets entrenched maladaptive schemas and unmet emotional needs from childhood.
• Combines experiential, cognitive and behavioural techniques; effective for chronic cases.

4. Transference-Focused Psychotherapy (TFP)

• Psychoanalytic-derived approach focusing on relationships and identity integration.

5. Short-term & adjunctive approaches

• Brief CBT interventions, skills groups, crisis management, and case management for social needs.

Medications — role and cautions

• No medication is approved specifically for BPD; meds target symptom domains or comorbid disorders.
• Antidepressants for mood symptoms, SSRIs for impulsivity and affective lability (mixed evidence).
• Mood stabilisers (e.g., lamotrigine, valproate) for severe impulsivity or mood swings.
• Antipsychotics for transient psychotic symptoms, severe agitation or brief mood dysregulation.
• Use lowest effective doses, review regularly, and combine with psychotherapy.

Working with families and carers

• Provide psychoeducation about BPD — explain symptoms are treatable and not deliberate ‘bad behaviour’.
• Teach skills to de-escalate crises and maintain boundaries (avoid reinforcing extremes).
• Encourage family involvement in therapy when safe and consented to (family sessions, skills coaching).
• Support carer wellbeing and offer resources for self-care and supervision.

Practical tips for clinicians

• Start with safety and alliance — consistent, predictable responses build trust.
• Use validation and clear limits: both acceptance and structure reduce enactments.
• Document crisis plans, escalation procedures and follow-up clearly.
• Seek supervision and team support — BPD work can be emotionally demanding.

Key takeaways

• BPD is a treatable condition — psychotherapy (especially DBT) reduces self-harm and improves functioning.
• Assessment must prioritise safety, suicidality and comorbidity.
• Families benefit from education, boundaries and involvement when appropriate.
• Therapist support and supervision improve care quality and reduce burnout.