How do you go about diagnosing a personality disorder?
Diagnosing a personality disorder is actually not dissimilar to diagnosing any mental health condition.
What are the behavioural patterns?
The first core part of it is actually to take a history. You need to talk to the individual, you need to understand a little bit about what their difficulties are in life, what are the patterns of behaviour that seem to occur day-in, day-out? Those patterns of behaviour, their core difficulties, tend to be a clue that there is some underlying personality disorder.
Secondly, one looks at how their interpersonal relationships are going, and that could be with peers, or authority figures, or with people in a relationship. That will start to give a clue, elements of dysfunction.
And then finally, work relationships, how are they operating? And it’s a consistent pattern, year-in, year-out, month-in, month-out, that starts to give clues that there’s a personality disorder. If there is a one-off event, or several events that have never occurred before in someone who’s fundamentally been pretty high functioning, it’s unlikely they’re going to have a personality disorder.
Patterns of behaviour
So it’s the enduring quality of it, over many years, and fairly predictable, consistent patterns of behaviour that give the clue that that individual has a personality disorder. The information that helps to provide that clue comes from multiple sources, the person themself, family members or other acquaintances who may know that person well.