What is borderline personality disorder?
Borderline personality disorder, sometimes called an emotionally unstable personality disorder, is a personality disorder. It involves a pervasive pattern of instability in relationships, self-image and emotions, including fear of abandonment and feelings of emptiness, together with pronounced impulsivity. It typically becomes apparent by early adulthood.
How does this personality disorder present?
Early difficulties may already be apparent towards the end of childhood, often through impulsive or reckless behaviour. Historical estimates cited in this article place prevalence at around 2% in the general population, 10% among people attending psychiatric consultations and 20% among psychiatric inpatients. The clinical figures discussed here describe around 70% women and 30% men, although clinical samples should not be taken as an exact picture of the population. The course varies considerably. A commonly described pattern is marked instability in early adulthood, with episodes of difficulty controlling emotions and impulses and frequent contact with mental health services. Suicide risk is a serious concern, especially in younger adulthood. Many people become more stable in relationships and work during their thirties and forties. The older literature cited in the original article reports suicide mortality approaching 10% in some clinical populations. Such figures are not a prediction of an individual’s future. Instability is a central feature: psychiatrist Bernard Granger describes a striking consistency in that instability. Just as something begins to provide an anchor, the person may feel compelled to break the connection. Relationship breakdowns and interruptions in work or social life can therefore recur. Life can feel as though it is constantly carrying the person from one crisis to another. Expressions such as emotional dysregulation, emotional overflow or heightened emotional reactivity describe how intense these experiences can be. Low mood, anxiety, boredom, emptiness, fragility and vulnerability may be prominent. Mood can shift from elation to distress within a very short time, sometimes within an hour. These rapid shifts can resemble aspects of bipolar disorder, although the two conditions are distinct and require careful assessment. Depressive episodes can be severe. Feelings of boredom and emptiness may be particularly difficult to tolerate. Substance use or risky behaviour may become ways of escaping these painful experiences. Impulsivity can also appear as intense anger, sometimes triggered by seemingly small events and directed towards oneself, others or both. In the moment, the person may feel overwhelmed by anxiety and seek an immediate way out. Self-injury, eating difficulties, substance use, risk-taking and suicidal behaviour may occur in this context. Suicidal acts can be impulsive. Understanding these behaviours as attempts to escape overwhelming distress does not make them less serious. Self-esteem and confidence are often very low. Psychotic symptoms or bipolar disorder may coexist, particularly during a personal crisis. Eating disorders can sometimes obscure an underlying pattern of borderline difficulties. An encouraging point is that symptoms and functioning can improve over time.
DSM-5 features of borderline personality disorder: a summary
- Intense attempts to prevent an actual or feared separation or abandonment.
- Very intense, unstable relationships in which another person may be viewed first as exceptionally good and later as deeply disappointing or rejecting.
- A markedly unsettled sense of identity, with sudden changes in self-image, values, goals or plans.
- Impulsive behaviour in more than one area that may cause harm, such as spending, substance use, unsafe driving or binge eating.
- Repeated suicidal behaviour, threats or self-injury.
- Strong emotional reactions and rapid mood shifts, often involving distress, irritability or anxiety that last hours rather than sustained episodes over weeks.
- A persistent feeling of inner emptiness.
- Very intense anger or difficulty managing it, sometimes with frequent outbursts or conflict.
- Brief periods of suspiciousness or pronounced dissociation during stress.
Possible origins of borderline personality disorder
Research has explored brain processes involved in difficulties regulating emotions. Childhood abuse, neglect or an unstable environment may play a role, but these experiences are not present in every person’s history. Personality develops through childhood, and a hostile or unpredictable environment can make that development more difficult. Biological, genetic, environmental and social factors may all contribute. None of these factors alone establishes a diagnosis or determines someone’s future. The disorder is not a limitation of intelligence, and meaningful social and occupational recovery is possible. The NIMH overview provides further information about the interaction of these factors.
How should borderline personality disorder be approached?
Diagnosis is clinical: there is no single biological test that establishes the disorder. Bipolar disorder is one important alternative or coexisting condition to assess. A careful diagnosis can help give a name to the person’s experience and guide them towards a suitably trained psychotherapist. Safety and the prevention of suicidal behaviour are priorities. The course is not inevitably one of progressive deterioration. Support should help identify people, activities and routines that provide stability. Treatment can be demanding and long term, and breaks in the therapeutic relationship need particular attention. Fear of rejection, impulsivity and anger may affect relationships with therapists as well as with loved ones. Maintaining a reliable therapeutic connection can help reduce crises, hospitalisations and suicidal behaviour. A dependable relationship can offer experiences that differ from earlier painful ones and become a source of stability. Medication does not specifically treat every aspect of the personality disorder, although a clinician may prescribe it for associated symptoms or other conditions, with the aims and duration reviewed individually.
Attachment and borderline personality disorder
Within Bowlby’s attachment framework, borderline difficulties are often discussed in relation to insecure attachment (French-language resource). Strongly conflicting feelings can make relationships unstable. Someone may idealise another person and then feel intensely rejecting towards them. This movement between attraction and rejection can itself maintain instability. Fear of abandonment may shape many relationship choices, including the choice of a romantic partner. Repeated requests for reassurance can leave the other person feeling exhausted and withdrawing, unintentionally contributing to the separation that was feared in the first place.
Psychotherapy for the disorder
One particularly relevant approach is Marsha Linehan’s dialectical behaviour therapy, or DBT, a structured and sequential treatment. A therapeutic agreement sets out goals, responsibilities and the framework for support. Contact between sessions, when offered, follows the programme’s agreed boundaries and is not a general promise of unlimited or overnight availability. Safety planning cannot be replaced by a promise not to attempt suicide. Some aspects of a full programme may be more difficult to provide in a single private practice than within a multidisciplinary service. Therapy encourages acceptance of oneself and recognition of what is helpful, alongside work towards change, rather than experiencing everything as either perfect or unbearable. People learn to recognise and consider more than one perspective. Psychoeducation is important: understanding one’s patterns can make it easier to step back from automatic reactions. DBT belongs to the cognitive behavioural tradition and includes work on assertiveness (French-language page). It also incorporates relaxation and mindfulness (French-language page). Mindfulness involves noticing present experience and emotions while becoming less entangled in fears about the future or the past. Group work may be offered alongside individual therapy.
Comparative research has also considered schema therapy (French-language resource) alongside other approaches developed for borderline difficulties, including mentalisation-based treatment and DBT.
Two important components of comprehensive DBT are:
- Individual therapy, in which therapist and patient review the week’s difficulties, often using a diary, and agree priorities. Suicidal behaviour and self-injury are addressed first, followed by behaviours that interfere with treatment and then difficulties affecting quality of life. Work focuses on using skills in everyday situations and identifying what gets in the way.
- Group skills training, commonly held weekly, covering mindfulness, interpersonal effectiveness, emotion regulation and distress tolerance. Individual work helps address crises and obstacles, while the group provides opportunities to learn and practise skills with others. Family work may be a useful addition, helping relatives understand the difficulties and respond to crises.
Authors, videos and references
A very good programme hosted by Professor Olivier Lyon-Caen with Professor Bernard Granger, a psychiatrist at Tarnier Hospital (in French).
Otto F. Kernberg, a pioneer in the study of this disorder (French-language overview).
Marsha Linehan: dialectical behaviour therapy.
English-language information about treatments for borderline personality disorder.
TCC Montréal published a guide to dialectical behaviour therapy in 2024 (in French). As always, the work shared by these generous North American colleagues deserves appreciation.