There are different ways to classify personality disorders, and experts often disagree about the best way to group them together. Generally, they agree that personality disorders lie on a spectrum, along with normal personality traits. So, some people may have some features of a personality disorder without having the entire disorder.

Some people may also show features of more than one personality disorder.

One of the main classification systems groups personality disorders into 3 main 'clusters'.

Cluster A

People with this type of disorder are generally described as having 'odd' or 'eccentric' thoughts or behaviours:

• Paranoid personality disorder: people with this disorder are suspicious and mistrustful of others, interpret other people’s motives as harmful, and may be hostile or emotionally detached.
• Schizoid personality disorder: this disorder causes someone to lack interest in social relationships and have an unemotional response to social interactions.
• Schizotypal personality disorder: this may cause people to behave eccentrically, have peculiar dress, have unusual or bizarre thoughts and beliefs, feel discomfort in social settings, and have trouble forming close relationships.

Cluster B

General features of this cluster group include unstable emotions and dramatic or impulsive behaviours:

• Antisocial personality disorder: this disorder may cause a disregard for the law or for the rights of others, with a lack of remorse, including lying and stealing, aggression, violence or illegal behaviour.
• Histrionic personality disorder: people with this disorder are highly emotional and dramatic, have an excessive need for attention and approval, and may be obsessed with their appearance.
• Borderline personality disorder: the main features include fear of abandonment, intense and unstable relationships, extreme emotional outbursts, deliberate self-harm or self-destructive behaviour and a fragile sense of self or identity.
• Narcissistic personality disorder: a pattern of inflated self-esteem, need for admiration, lack of empathy or concern for others, and fantasies of success, power or beauty.

Cluster C

General features of these disorders include anxious and fearful thoughts and behaviour:

• Avoidant personality disorder: people with this disorder avoid social interaction and are extremely sensitive to negative judgements by others; they may be timid and socially isolated with feelings of inadequacy.
• Obsessive-compulsive personality disorder: people with this disorder are preoccupied by rules, orderliness and value work above other aspects of life. They are perfectionistic and have a need to be in control. Note that this is different from obsessive-compulsive disorder (OCD), which is a form of anxiety disorder.
• Dependent personality disorder: this disorder causes a fear of being alone and a need to be taken care of, difficulty separating from loved ones or making independent decisions. People may be submissive and even tolerate domineering or abusive relationships.

Some people with personality disorders may be at risk of harming themselves or others. You can call Lifeline on 13 11 14, or dial triple zero (000) if you or someone you know has attempted to or is at risk of attempting to harm themselves or someone else.