Approach to diagnosing personality disorder
Personality is a person’s unique combination of general tendencies or traits, desires, beliefs, concerns, coping mechanisms, and life story (narrative). Personality is considered normal when it allows a person to adapt to their circumstances and environment, but what is considered normal can depend on cultural norms (eg high emotional expression is expected in some societies but not others). Personality disorder occurs when features of a person’s personality are inflexible or maladaptive, and interfere with the person’s ability to adapt to or manage changes in their circumstances or environment. Personality disorder involves both:
- problems in functioning of aspects of the self (eg identity, self-worth, accuracy of self-view, self-direction)
- interpersonal dysfunction (eg problems developing and maintaining close and mutually satisfying relationships; impaired ability to understand others’ perspectives and to manage conflict in relationships).
The aetiology of personality disorder is complex, involving an interplay between factors that predispose a person to a vulnerable temperament (eg familial risk, prenatal exposures), deficits in the caregiving environment in infancy, and ongoing maladaptive social experiences1. This results in the deficits in emotional regulation and social communication seen in a person with personality disorder. Although adverse life experiences in childhood (eg trauma, abuse, neglect) are associated with personality disorder, and should be considered when personality disorder is suspected, adverse experiences are nonspecific to personality disorder. In addition, some patients with personality disorder report no adversity in childhood.
Personality disorder is one of the most common psychiatric disorders, affecting approximately 10% of the Australian population. However, the prevalence in clinical settings is higher because people with personality disorder seek treatment more frequently—personality disorder is prevalent in a quarter of patients attending primary care and up to half of patients attending specialist psychiatric services.
Personality disorder usually becomes apparent during the transition from childhood to adulthood, when the capacity for self-reflection and a life narrative is developed. Disturbances in cognition, emotions, behaviour and relationships must be:
- displayed across a range of situations and contexts
- associated with substantial distress or significant impairment in important areas of functioning (eg personal, family, social, educational, occupational)
- relatively stable across situations and over a period of years (ie part of the individual’s ‘usual self’)
- distinct from periods of another mental state disorder (eg depressive or manic episodes, periods of intoxication).
Timely diagnosis of personality disorder is key, because untreated personality disorder can disrupt the complex developmental tasks required to achieve adult role functioning and cause severe, long-term adverse outcomes, including severe functional disability, physical illness, self-harm and suicide. Suspect personality disorder in a person who has persistent interpersonal difficulties (eg difficulties with empathy, intimacy, understanding others’ perspectives, managing conflict) or difficulties in self-management (eg identity disturbance, self-reflection, self-worth). To establish the impact and persistence of the maladaptive behaviours, consult at least one other source of information, including
- a longitudinal history provided by the patient
- information from previous clinicians or clinical records
- collateral information from the patient’s family, carers or significant others.
Patients with personality disorder usually present during times of acute crisis, following self-harm, or due to poor physical health. They are particularly vulnerable to self-harm and suicidal behaviour, due to their sometimes impulsive and self-damaging behaviour. For information on how to recognise patients at risk of suicide, see here.
The high rate of co-occurring psychiatric disorders (eg anxiety disorders, major depression, eating disorders, alcohol and other drug problems) may cause diagnostic confusion. This can lead to missed, delayed or incorrect diagnosis, unnecessary investigation and use of pharmacotherapy that may be ineffective or harmful. There is a strong association between personality disorder and alcohol and drug problems—studies report a lifetime prevalence of such problems of over 50% in people with personality disorder. Overview of substance use and addictive behaviours contribute to premature mortality in people with personality disorder, so it is important that they are detected, assessed and treated.
When a diagnosis of personality disorder is made, it should be classified according to the severity and any trait domains or patterns, which describe the prominent characteristics of the person’s personality.