Borderline personality disorder: diagnosis, clinical features and pathophysiology

People with borderline personality disorder often have difficulties in maintaining social relationships and they have a high risk of suicide.

Man in corner with borderline personality disorder


Borderline personality disorder is characterised by impulsiveness and mood instability, with patients feeling empty and having a negative self-image. Patients are at an increased risk of suicide.

The exact cause of borderline personality disorder is unclear, and it is best understood through a biopsychosocial model, where genetic factors and life experiences interplay to affect brain development during childhood. Diagnosis is made using the DSM-IV criteria and is often contentious, as personality is part of a patient’s identity and it may feel like a personal attack. However, with treatment the prognosis is often good.

Personality describes our way of thinking, feeling and behaving. It is a complex term that underpins our sense of self. For some people, the way they perceive the world and relate to it seems to be different from what is culturally expected. A personality disorder might be diagnosed when this causes distress and difficulty.

Borderline personality disorder is the most common personality disorder. It is characterised by a pattern of impulsiveness and mood instability. It has a prevalence of around 0.7% in the general population and affects men and women equally[1]

People with borderline personality disorder are more likely to visit their GP frequently than those without the condition. The prevalence of borderline personality disorder is between 4-6% of patients using primary care services, and around 50% of patients using mental healthcare services[1]

A diagnosis of borderline personality disorder is not usually made until a person is aged over 18 years. However, features may be present in adolescence.

Clinical features

Mood instability is a defining characteristic of borderline personality disorder. Patients may describe feeling ‘up’ one minute and ‘down’ the next, and find it difficult to understand why this happens. Thoughts and feelings can be difficult to manage and some people self-harm as a way of managing distress. This may take the form of cutting, ligaturing or taking an overdose.

Patients with borderline personality disorder often have difficulties in maintaining social relationships. They often find themselves in conflict with others, which can lead to social isolation and difficulties at work. They may also have problematic attachment patterns, causing them to have intense, short-lived relationships.

Patients may also have a poor sense of who they are and can feel empty and negative about themselves. Symptoms of psychosis can occur, but are usually brief and linked to times of extreme emotional instability.

Borderline personality disorder is often associated with other mental health problems such as anxiety, depression, eating disorders, post-traumatic stress disorder and substance misuse. The overlap of symptoms with other psychiatric disorders can make diagnosis difficult; for example, it can be unclear if a symptom such as depression is a comorbidity or related to the disorder itself.

People with borderline personality disorder are at a high risk of suicide; 60–70% attempt suicide at some point and 10% die as a result[2]
. Childhood stress can also affect physical health in later life and is a risk factor for systemic inflammation, cardiovascular disease and diabetes[3]
. This may help to explain the high rate of physical problems in this patient group.


Criteria for the diagnosis of personality disorders, including borderline personality disorder, are set out in two classification systems: the ‘Diagnostic and statistical manual of mental disorders — fifth edition (DSM-V)’, produced by the American Psychiatric Association[4]
, and the ‘International statistical classification of diseases and related health problems — tenth revision (ICD-10)’, produced by the World Health Organization[5]

Clinical guidance on the treatment and management of borderline personality disorder[1]
 by the National Institute for Health and Care Excellence (NICE) uses an earlier edition of DSM criteria (DSM-IV), which is broadly similar to the DSM-V criteria and currently used in practice (see Diagnostic criteria).

Diagnostic criteria

A pervasive pattern of instability of interpersonal relationships, self-image and affects (emotional expression), and marked impulsivity beginning by early adulthood and present in a variety of contexts, as indicated by five (or more) of the following:

1. Frantic efforts to avoid real or imagined abandonment. Note: do not include suicidal or self-mutilating behaviour covered in criterion 5.

2. A pattern of unstable and intense interpersonal relationships characterised by alternating between extremes of idealisation and devaluation.

3. Identity disturbance: markedly and persistently unstable self-image or sense of self.

4. Impulsivity in at least two areas that are potentially self-damaging (for example, spending, sex, substance abuse, reckless driving, binge eating). Note: do not include suicidal or self-mutilating behaviour covered in criterion 5.

5. Recurrent suicidal behaviour, gestures, or threats, or self-mutilating behaviour.

6. Affective instability due to a marked reactivity of mood (for example, intense episodic dysphoria, irritability, or anxiety usually lasting a few hours and only rarely more than a few days).

7. Chronic feelings of emptiness.

8. Inappropriate, intense anger or difficulty controlling anger (for example, frequent displays of temper, constant anger, recurrent physical fights).

9. Transient, stress-related paranoid ideation or severe dissociative symptoms (a sense of being unreal or not present in your own body).

Source: American Psychiatric Association

Diagnosing someone with a personality disorder is often contentious. Clinicians and patients have questioned the validity of the diagnosis and how it is diagnosed[6]
, and some consider the term stigmatising; personality is considered to be fundamental to our identity and a suggestion that it is disordered can be perceived to be a personal attack. However, the diagnosis can also be useful, and may help a person understand their difficulties and seek appropriate help.

Risk factors

Genetic and environmental factors are both believed to have a role in the development of borderline personality disorder. Although personality traits are known to be influenced by genetics, no specific genes associated with borderline personality disorder have been identified.

Many, but not all, people with borderline personality disorder have a history of childhood difficulties, ranging from neglect to emotional, physical and sexual abuse.

A childhood where thoughts, behaviours and experiences were trivialised or punished by a carer seems to be a noteworthy factor. Consequently, the labelling of emotions and the ability to soothe feelings may be impaired, leading to emotional dysregulation (problems controlling emotions). The ability to trust thoughts and feelings may also be affected, leading to issues with identity[7]


The exact underlying cause of borderline personality disorder is unclear. This can make it particularly challenging to understand how and why certain medicines or psychological therapies work.

A biopsychosocial model, where genetic factors and life experiences interplay, can be used to understand how borderline personality disorder develops. The brain is a complex organ that continues to grow and change throughout life. Children are dependent on carers for all their needs, and because neural pathways develop rapidly during this time, a difficult childhood can have a significant effect on brain development. Therefore, our early experiences can affect how our brain is shaped, which in turn affects the way we behave in society[3]

Advances in neuroscience are helping to improve our understanding. Stimulation of the hypothalamus-pituitary-adrenal (HPA) axis leads to the production of the glucocorticoid cortisol. Chronic stress, such as that associated with childhood adversity, has been shown to alter the activity of the HPA axis and the amount of cortisol produced[3]
. This can affect how we respond to perceived stressors in the future.

The brain areas of particular interest in borderline personality disorder are the limbic system and the frontal areas. The limbic system is a collection of structures that includes the amygdala and hippocampus. This area is believed to regulate emotion (the amygdala regulates fear and anxiety and the hippocampus is responsible for memory). The frontal areas of the brain, for example the prefrontal cortex, can be activated to inhibit emotional impulses and regulate behaviour. By engaging this part of the brain, people can control how they express feelings.

Neuroimaging studies have found there is a reduction in volume of the amygdala in people with borderline personality disorder[3]
. This is believed to be caused by excitotoxicity, a process in which nerve cells are damaged by excessive stimulation (e.g., stress).

It has been suggested that the amygdala is also more sensitive in people with borderline personality disorder; when people with borderline personality disorder are shown images designed to elicit unpleasant emotions, activation of the amygdala — as shown on a function magnetic resonance imaging scan — has been found to be higher compared with those without the disorder[8]


In a 16-year follow-up study of 290 patients with borderline personality disorder, 78% no longer met the criteria for a personality disorder diagnosis after eight years[9]
. However, the disorder recurred in some patients included in the study, and remission took longer to achieve than for other mental health conditions.

The study found around 40% of patients remained in remission for at least eight years (defined as having only minor symptoms and good global functioning). This rate is lower than for other mental health conditions.


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Borderline personality disorder: diagnosis, clinical features and pathophysiology

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Christopher Todd is a mental health pharmacist, Justine Raysnford is a mental health pharmacist and Kay Radcliffe is a third year psychologist in clinical training, all at Leeds and York Partnership NHS Foundation Trust.



[1] National Institute for Health and Care Excellence. Borderline Personality Disorder: Treatment and Management. London: NICE 2009.

[2] Oldham JM. Borderline Personality Disorder and Suicidality. Am J Psych 2006;163:20–26.

[3] Tyrka A, Burgers D, Philips N et al. The neurobiological correlates of childhood adversity and implications for treatment. Acta Psychiatrica Scandinavica 2013;128:434–437.

[4] American Psychiatric Association. Diagnostic and statistical manual of mental disorders. Fifth Edition. Arlington: American Psychiatric Association 2013.

[5] World Health Organization. The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10). Geneva: WHO 1992.

[6] Sarkar J & Duggan C. Diagnosis and classification of personality disorder: difficulties, their resolution and implications for practice. Adv Psych Treat 2010;16:388–396.

[7] Linehan MM. Cognitive-Behavioural Treatment of Borderline Personality Disorder. London: Guildford Press 1993.

[8] Koenigsberg HW, Siever LJ, Lee H et al. Neural correlates of emotion processing in borderline personality disorder. Psychiatry Res 2009;172:192–199.

[9] Zanarini M, Frankenburg F, Reich B et al. Attainment and Stability of Sustained Symptomatice Remission and Recovery Among Patients With Borderline Personality Disorder and Axis II Comaprison Subjects: A 16 year Prospective Follow-up Study. Am J Psych 2012;169:476–483.

Last updated
Clinical Pharmacist, CP, September 2014, Vol 6, No 7;6(7):DOI:10.1211/PJ.2014.20066368

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