Borderline personality disorder

It is a personality disorder marked by instability of self-image, relationships and emotions, together with impulsivity.¹ It is not a character flaw or a way of “seeking attention”: it is a recognised clinical condition, with an established diagnosis and treatment.^1,3

Lifetime prevalence in the general adult population is estimated at between 0.7% and 2.7%, and it is considerably more common among people who use mental health services: about 12% in psychiatric outpatient clinics and 22% in inpatient units.¹ Recognising it early allows appropriate treatment to start sooner, which can reduce suffering.¹ In the World Health Organization’s classification (ICD-11), personality disorders are described by severity, and the “borderline pattern” is a specifier of its own.⁸ In the American Psychiatric Association’s DSM-5-TR it remains a separate diagnosis.⁹

The signs described in current classifications include:¹

• intense fear of abandonment and efforts to avoid it;
• intense, unstable relationships that swing between idealisation and devaluation;
• an unstable self-image or sense of identity;
• impulsivity that can cause harm, for example in spending, substance use or driving;
• self-harm, or suicidal threats and attempts;
• rapid, intense mood changes in response to everyday events;
• a chronic feeling of emptiness;
• intense anger that is hard to control;
• transient paranoid ideas or dissociation at times of severe stress.

Great sensitivity to what feels like rejection lies at the heart of many of these difficulties.² Having some of these experiences now and then does not mean having the disorder: the diagnosis requires a persistent pattern, present across different settings.⁹

There is no single cause. Current evidence points to an interaction between genetic factors and adverse childhood experiences, such as neglect or maltreatment.¹ The neurobiological mechanisms are still being studied and remain unclear.¹

Understanding this interaction helps to move away from blame, whether of the person or of the family, and to focus on what can change: skills to regulate emotions, manage crises and keep relationships more stable.

The diagnosis is clinical. It rests on a careful assessment of life history, patterns in relationships, functioning at work or in education, and other disorders that may be present; semi-structured interviews allow a reliable diagnosis.^1,3

Because it describes a long-standing pattern, it should not be decided from a single moment, especially during a crisis: NICE recommends reviewing the diagnosis when it was made in an emergency.³ It is also important to identify conditions that often occur alongside it, such as depression, substance use, post-traumatic stress disorder, ADHD, bipolar disorder or eating disorders.¹ An incorrect diagnosis often leads to medication-based treatments that rarely succeed.²

Psychotherapy is the treatment of choice.¹ Several approaches have been tested in randomised trials:^1,4

• dialectical behaviour therapy (DBT), focused on skills for emotional regulation, distress tolerance and relationships;
• mentalisation-based treatment (MBT), which helps people understand their own mental states and those of others;
• transference-focused psychotherapy;
• schema therapy.

A 2020 Cochrane review of 75 trials and 4,507 participants concluded that psychotherapies tailored to this disorder reduce symptom severity compared with usual treatment (moderate-quality evidence); the benefits for self-harm, suicide-related outcomes and social functioning were based on low-quality evidence.⁴ DBT and MBT are the most studied, and no approach has proved superior to the others.^1,4

NICE advises against brief interventions of less than three months aimed specifically at this disorder outside a structured service, and recommends considering a comprehensive DBT programme for women for whom reducing recurrent self-harm is a priority.³ Not everyone responds sufficiently, which is why progress is monitored and the plan adjusted.¹

No medicine has consistently been shown to treat the core features of the disorder.^1,5 NICE recommends that medication should not be used specifically for borderline personality disorder or for individual symptoms, such as repeated self-harm or emotional instability, and that antipsychotics should not be used for medium- and long-term treatment.³ A 2022 Cochrane review found no difference from placebo in the main outcomes, with very low-certainty evidence.⁵

Medication can, however, be part of the treatment of associated conditions, such as depression, anxiety or post-traumatic stress disorder, following the recommendations for each.^1,3 During a crisis, NICE allows short-term use with close review.³ When several medicines are being taken without a clear indication, reviewing the plan aims to reduce what is unnecessary.³

A crisis plan is prepared together, in advance, and written down. According to NICE, it identifies what may trigger a crisis, the self-management strategies that usually work and how to get help when those strategies are not enough, including out-of-hours contacts.³ After each crisis, what helped is reviewed and the plan is updated.³

The risk of self-harm and suicide is real in this disorder.¹ Suicidal thoughts, serious self-harm or risk to yourself or others are reasons to seek urgent help straight away.

Yes, for many people. Most gradually enter symptomatic remission, and evidence-based psychosocial treatments can speed up that improvement.²

A US study followed 290 people with this disorder, first assessed during a hospital admission. Over 10 years, 93% had a remission of symptoms lasting at least two years and 86% a sustained remission of at least four years; 50% achieved recovery, defined as remission with good social and vocational functioning.⁶ At 16 years of follow-up, sustained remission was much more common than full recovery, and relapses were possible.⁷

Over time, self-harming behaviour and proneness to crisis can decrease, even when some emotional sensitivity remains.² These figures give reasons for hope, and also show that functioning at work and in relationships deserves attention of its own in treatment, beyond the symptoms.^2,7

Family members and those close to the person often experience the intensity of crises at first hand. NICE recommends asking the person directly whether they want their family involved in their care and, with their consent and respecting confidentiality, encouraging that involvement and telling the family about support groups where they exist.³

• Understanding the disorder helps to make sense of reactions without always taking them personally.
• Knowing the crisis plan means knowing what to do and when to ask for help.
• Looking after yourself matters too: those who support others need support as well.

The assessment can take place in a psychiatric consultation, in person in Lisbon or by video consultation, in Portuguese, English or Spanish.