A diagnosis is made via a medical professional’s evaluation, based on specific diagnostic criteria.
Medical professionals base the diagnosis of a specific personality disorder on lists of personality traits (criteria) provided for each disorder in the Diagniostic and Statistical Manual of Mental Disorders (DSM, latest version).
Some individuals with a personality disorder are distressed by their behaviour and actively seek treatment. Others cannot see a problem with their own behaviour. Thus, they tend not to seek help on their own. Instead, they may be referred by their friends, family members, or a social agency because their behaviour is causing difficulty for others.
When individuals with a personality disorder seek help, the reason is likely to be to get help with symptoms such as anxiety, depression, or substance use or with the problems created by their personality disorder such as divorce, unemployment, or loneliness – rather than the disorder itself.
When individuals report such symptoms or problems, medical professionals usually ask them questions to determine whether a personality disorder might be involved. For example, medical professionals ask how they view themselves and others and how they respond when people react negatively to their behaviour.
A medical professional suspects a personality disorder if individuals:
- Persist in viewing themselves or others in ways that differ from reality;
- Describe a pattern of inappropriate thoughts or behaviour that they do not change despite the negative consequences of such behaviour; and/or
- Are distressed by their behaviour and/or its consequences or cannot function adequately because of their behaviour.
The inappropriate thoughts and behaviours may involve how individuals see and understand themselves and others, how they interact with others, and/or how well they control their impulses.
Such thoughts and behaviours are considered a disorder only if they are persistent (not just once in a while) and if an individual keeps doing them even though they cause the individual distress or difficulties in daily life.
Also, the thoughts and behaviours must have started during adolescence or early adulthood, not later in life.
To help confirm the diagnosis, medical professionals may talk with the individual’s friends and family members to obtain additional information. Without such help, the medical professional and the individual might remain unaware of the individual’s role in creating the problems.