Between 10 and 13% of the general population have some form of personality disorder (Girolamo and Dotto, 2000). This includes borderline personality disorder and anti-social personality disorder.

We all have individual characteristics called personality traits. These affect the way we think, feel and behave. Someone may be described as having a personality disorder if these characteristics cause regular and long term problems in the way they cope with life, interact with others or how they respond emotionally.

Each type of personality disorder includes specific symptoms. Some typical symptoms are:

• not trusting other people, feeling threatened
• lack of emotion
• extreme fear of rejection, becoming dependent on others
• appearing not to care about other’s opinions of them
• reckless and impulsive behaviour
• being overly dramatic and like to be the centre of attention
• perfectionism
• not seeing the bigger picture.

Personality disorder is probably the most misunderstood diagnosis in mental health. Personality disorder was included in the definition of mental disorder in the 2007 amendments to the Mental Health Act. But there is still controversy over its inclusion.

In 2003 the National Institute for Mental Health produced guidance, Personality Disorder: No longer a diagnosis of exclusion, making it clear that people with personality disorders should receive appropriate care and should not be excluded from services because of their diagnosis.