Personality disorders

Personality disorders (PD) are a group of mental health conditions that are characterised by inflexible and maladaptive patterns of behaviour, cognition and inner experience (thoughts and feelings) that are exhibited across the board and remain persistent.

There are 10 distinct types that can be grouped into 3 clusters/categories which we will discuss below.

🏘️ Epidemiology

• Onset - it typically begins in late childhood or adolescence and persists into adulthood.
• Prevalence - within the UK an estimated 13.9%-17.3% of an individuals ≥16 years old screen positive for personality disorders.
• Gender differences
• Onset: Typically begins in late childhood or adolescence, with traits persisting into adulthood.
• Prevalence:
• Estimated to be 9-11.2% in the general population.
• Higher prevalence among white populations as compared to other populations.

Pathophysiology

The development of personality disorders are influenced by both genetic and environmental factors, with plenty of heterogeneity between patients.

• Genetic factors - research shows a 40%-60% heritability estimate. Some genetic variations within the hypothalamic-pituitary-adrenal (HPA) axis have been linked to increased susceptibility, but more so it seems to have a link with early emotional trauma and chronic stress.
• Environmental factors - adverse childhood events, early maternal stress exposure and prenatal stress exposure (maternal anxiety, smoking and alcoholism) all have a strong link to predisposition of PDs (especially borderline PD). Children with a history of abuse and neglect are 4x likely to develop a PD (especially avoidant personality disorder).

Let’s discuss the pathophysiology in a little more depth:

Underlying neurobiological mechanisms involve disruptions in neurotransmitter systems, brain structure, and stress regulation pathways.

• Prefrontal cortex & amygdala dysfunction:
• The prefrontal cortex (responsible for impulse control and decision-making) has reduced activity in individuals with personality disorders, leading to poor regulation of emotions and behaviors.
• The amygdala (involved in emotional processing and fear response) shows hyperactivity, which may explain the heightened emotional reactivity and impulsivity seen in many personality disorders.
• Dopaminergic dysfunction
• Dopamine plays a key role in cognition, impulse control, and emotional regulation. Some studies have shown that dopamine receptor antagonists may provide symptomatic benefit in borderline personality disorder.
• Oxytocin dysfunction
• Oxytocin is involved in emotional bonding and social behavior, and has been implicated in borderline personality disorder. Studies have shown that individuals with borderline personality disorder may have lower oxytocin levels - contributing to difficulties in interpersonal relationships, emotional dysregulation, and difficulties trusting others.

😷 Presentation

We will discuss the features of each personality in more depth below. However, it is important to note the core features of all PDs as well as some commonalities across the board.

• Core features
• Pervasiveness – affects multiple aspects of life.
• Inflexibility – behaviours and thoughts remain unchanged despite negative consequences.
• Maladaptive – leads to significant distress and/or functional impairment.
• Lack of insight - individuals with the PD deem their behaviour and thinking to be the non-problematic and not deviating from the norm.

💯 Criteria

The diagnostic criteria according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) states that for us to be able to diagnose a PD:

• At least 2 or more of the following deviate significantly from cultural expectations:
• Cognition-perception - perceives events, others, or self in an inappropriate way)
• Affectivity regulation - or emotion regulation, is the ability to manage and modulate emotional states to adapt to environmental demands, including negative emotions.
• Interpersonal functioning 
• Impulse control
• The persistent pattern of maladaptive traits must cause significant distress or impaired functioning in social, occupational, and other important areas.
• The pattern is stable and has an early onset (traced back to at least adolescence or early adulthood)
• Is not caused by another mental disorder, substance abuse, or other medical condition

💡 If the individual is <18 years old the pattern must have been present for ≥ 1 year, except for antisocial personality disorder, which cannot be diagnosed in patients < 18 years.

🧰 Management

Classification and types

Cluster A personality disorders

Cluster A PDs are deemed to be the “weird” personality types. They have odd and eccentric behaviours with an inability to form interpersonal relationships.

There are 3 PDs that fall under cluster A:

1. Paranoid personality disorder
2. Schizoid personality disorder
3. Schizotypal personality disorder

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Paranoid personality disorder

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Schizoid personality disorder

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Schizotypal personality disorder

Cluster B personality disorders

Cluster B PDs are deemed to the “wild” personality types. They have dramatic, erratic, and emotional behaviours.

There are 4 PDs that fall under cluster B:

1. Antisocial personality disorder
2. Borderline personality disorder
3. Histrionic personality disorder
4. Narcissistic personality disorder

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Antisocial personality disorder

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Borderline personality disorder

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Histrionic personality disorder

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Narcissistic personality disorder

Cluster C personality disorders

Cluster C PDs are deemed to be the “worried” personality types. They are characterised by anxious, fearful, and avoidant behaviours.

There are 3 PDs that fall under cluster C:

1. Avoidant personality disorder

2. Dependent personality disorder

3. Obsessive-compulsive personality disorder

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Avoidant personality disorder

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Dependent personality disorder

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Obsessive-compulsive personality disorder

Summary