This week the teenager who received a life sentence for murdering his parents, turned media attention to a little known psychiatric diagnosis called narcissistic personality disorder. One of the most shocking things about the case seems to be that Blackwell had no trace of a ‘troubled background’, and the media were left searching for reasons for an unreasonable act.
In The Times Minette Marin wondered whether Blackwell was at the mercy of his genes. Ultimately this is a question of free will – do we really have the power to make our own decisions or do we simply carry out the bidding of our genes and environment?
It’s easy and very common to set up this ‘either’, ‘or’ question, despite the fact it doesn’t help work out what is going on here. A more useful thought is to imagine a sliding scale of free will, where perhaps some people have more free will than others.
Along similar lines, The Observer discussed how parents may feel they have little control over how their children turn out. This, however, is something that psychologists have recognised already – finding that it is a child’s peers who have the largest effect on personality development.
The Telegraph pointed out that narcissistic personality disorder is more of an American construct than a British one – along with the suggestion everyone is narcissistic to a certain extent.
This point brings out the most important problem with so-called personality disorders and their diagnosis. The categories are often fairly arbitrary, culturally defined and not widely agreed upon. Personality disorders are sliding scales, not on or off categories, and many of the categories themselves have very fuzzy boundaries.
In addition, most of the personality disorders recognised by psychiatrists in the Diagnostic and Statistical Manual of Mental Disorders show high levels of comorbidity. In other words if you’re diagnosed with one, then you’re likely to be diagnosed with others as well. It all comes down to the convenience of giving someone a label.
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Bear that in mind as you read BBC News’ description of narcissistic personality disorder.