Personality refers to a combination of unique traits expressed in thoughts, behaviours, feelings and interpersonal functioning. It is relatively stable over time and over situations. Personality disorders are pervasive, persistent and pathological. It can be assessed using semi-structured interviews (1), file research (2), using observations (3) and using heteroanamnesis, asking someone close to the person. They are dimensional in nature and the prevalence of a personality disorder is ±10%. The prevalence of personality disorders in prisons is ±60-70%. There is high comorbidity between the personality clusters.

Psychopathic people have no shame, poverty of emotions and manipulate others for personal gain. They seem unable to learn from experience, are insensitive to threats and immune to anxiety that keeps most people from breaking the law. Boldness (1), meanness (2) and impulsivity (3) underly psychopathy.

Problems with dopamine systems are involved in cognitive problems. Problems with serotonin systems are involved in anger and impulse control. Problems with MAO systems are involved with aggression. A dysfunctional amygdala leads to either hyper-emotionality or hypo-emotionality. A lack of frontal cortical control leads to impulses.

Poverty (1), exposure to violence (2) and parenting qualities of negativity (3), inconsistency (4) and low warmth (5) predict antisocial behaviour.

People with narcissistic personality disorder strive to bolster their self-esteem, might have fragile self-esteem and overindulgence of parents might lead to an increase of narcissism.  

People with borderline personality disorder have a lower serotonin function, disrupted connectivity between the prefrontal cortex and the amygdala, deficits in the prefrontal cortex and increased activation of the amygdala.

Linehan’s diathesis-stress theory states that BPD develops when people who have difficulty controlling their emotions because of a biological diathesis are raised in a family environment that is invalidating. In an invalidating environment, the person’s feelings are discounted and disrespected.

Beck’s cognitive model states that maladaptive cognitions shape our ideas negatively and this can play a role in the development of personality disorders. Young’s schema theory states that maladaptive schemas that used to be adaptive play a role in the development of personality disorders. Operant conditioning and classical conditioning, as well as modelling, can play a role in the development of personality disorders. Immature defence mechanisms (e.g., splitting) can also play a role in the development of personality disorders.

Common factors in all treatment include intensive and prolonged treatment, the use of a consistent model and using an incentive to change. An incentive to change is necessary for treatment, as well as a safe environment with a clear structure and attachment figures.

The dialectical behaviour therapy consists of four steps:

1. Change dangerously impulsive behaviour
2. Focus on modulating extreme emotionality
3. Improving relationships and self-esteem
4. Promote connectedness and happiness