National Drug Strategy
National Drug Strategy

Comorbidity of mental disorders and substance use: a brief guide for the primary care clinician

8.1 Personality disorders

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A personality disorder is an enduring pattern of inner experience, of seeing the world and relating to others in a manner that markedly deviates from cultural expectations, and includes, and results in, problematic and habitual behaviours that are pervasive and inflexible.

The onset of personality disorders occurs in adolescence or early adulthood, is stable over time, leads to impairment or distress and is not due to mental disorder or substance use.

Personality disorders are long-standing and maladaptive patterns of perceiving and responding to other people and to stressful circumstances.

Personality traits are conspicuous features of personality and are not necessarily pathological, although certain styles of personality traits may cause interpersonal problems. Personality disorders are not regarded as illnesses. However, some dominant personality traits and personality disorders can be modified and some managed on a systemic level.

8.1.1 Personality disorder subtypes

Cluster A personality disorder

Includes paranoid, schizoid and schizotypal types. Individuals display odd and eccentric behaviour.


Person displays patterns of distrust and suspiciousness such that others’ motives are interpreted as malevolent.


Person displays a pattern of detachment from social relationships and a restricted range of emotional expression.


Person displays a pattern of acute discomfort in close relationships, cognitive or perceptual distortions, and eccentricities of behaviour.

Cluster B personality disorder

Includes antisocial, borderline, histrionic and narcissistic types. Individuals display dramatic, erratic and emotional behaviour.


Person displays a pattern of disregard for, and violation of, the rights of others.


Person displays patterns of instability in interpersonal relationships, self image and effects as well as marked impulsivity.


Person displays patterns of excessive emotionality and attention-seeking behaviour.


Person displays patterns of grandiosity, need for admiration and lack of empathy.

Cluster C personality disorder

Includes avoidant, dependent and obsessive compulsive types. Individuals display anxious and fearful behaviours.


Person displays patterns of social inhibition, feelings of inadequacy and hypersensitivity to negative evaluation.


Person displays patterns of submissive and clinging behaviour relating to the excessive need to be taken care of.

Obsessive compulsive

Person displays patterns of preoccupation with orderliness, perfectionism and control.

Personality disorders not otherwise specified

Personality disorders not otherwise specified are those where: Of all the different types of personality disorders, Cluster B personality disorders (including narcissistic, histrionic, borderline and antisocial) come to the attention of health providers and authorities the most. People with antisocial personality disorders frequently end up in the criminal justice system(312, 313).

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8.1.2 Management approaches

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