Personality disorders form a class of mental disorders that are characterized by long-lasting rigid patterns of thought and behaviour. Because of the inflexibility and pervasiveness of these patterns, they can cause serious problems and impairment of functioning for the persons who are afflicted with these disorders.
Personality disorders are seen by the American Psychiatric Association as an enduring pattern of inner experience and behaviour that deviates markedly from the expectations of the culture of the individual who exhibits it. These patterns are inflexible and pervasive across many situations. The onset of the pattern can be traced back at least to the beginning of adulthood. To be diagnosed as a personality disorder, a behavioural pattern must cause significant distress or impairment in personal, social, and/or occupational situations.
There are ten personality disorders, which are grouped into three clusters:
Cluster A (odd or eccentric disorders)
- Paranoid personality disorder
- Schizoid personality disorder
- Schizotypal personality disorder
Cluster B (dramatic, emotional, or erratic disorders)
- Antisocial personality disorder
- Borderline personality disorder - BPD
- Histrionic personality disorder
- Narcissistic personality disorder
Cluster C (anxious or fearful disorders)
- Avoidant personality disorder
- Dependent personality disorder
- Obsessive-compulsive personality disorder (not the same as Obsessive-compulsive disorder)