Almost everyone is pretty screwed up. That's not my opinion, that's official - according to a new paper in the latest British Journal of Psychiatry.

Make sure you're sitting down for this. No less than 48% of the population have "personality difficulties", and on top of that 21% have a full blown "personality disorder", and another 7% have it even worse with "complex" or "severe" personality disorders. That's quite a lot of people. Indeed it only leaves an elite 22.5% with no personality disturbances whatsoever. You're as likely to have a "simple PD" as you are to have a normal personality, and fully half the population fall into the "difficulties" category. I have difficulties with this. Where do these results come from? The Adult Psychiatric Morbidity Survey, which is a government study of the British population. They phoned up a random sample of several thousand people, and gave them the SCID interview, in other words they asked them questions. 116 questions in fact. 48% of people answered "yes" to enough questions such that, according to their criteria, they had "personality difficulties". They defined "personality difficulties", which is not a term in common use, as being "one criterion less than the threshold for personality disorder (PD)" according to DSM-IV criteria. So what? Well, as far as I'm concerned, that means simply that "personality difficulties" is a crap category, which labels normality as pathological. I can tell that most of people with "difficulties" are in fact normal because they are the literally the norm. It's not rocket science.

Thus we can conclude that "personality difficulties" should either be scrapped or renamed "normal". In which case the weird minority of people without any such features should be relabelled. Maybe they are best known as "saints", or "Übermenschen", or perhaps "people who lie on questionnaires". However, this is not what the authors say. They defend their category of Personality Difficulties on the grounds that this group are slightly more likely to have a history of "issues" than the elite 22.5 percent, e.g. homelessness (3.0% vs. 1.6%), 'financial crisis' (10.1% vs. 6.8%), or having had treatment for mental illness (11% vs 6%). They say:

The finding that 72% of the population has at least some degree of personality disturbance is counter-intuitive, but the evidence that those with ‘personality difficulty’ covering two out of five of the population [it's actually closer to half], differs significantly from those with no personality disturbance in the prevalence of a history of running away from home, police contacts, homelessness... shows that this separation is useful from both clinical and societal viewpoints.

Well, yeah...but no. The vast majority (90+%) of people with Personality Difficulty had no history of these things. It's true that, as a group, they have higher rates, but all this tells you is that some of them have problems. I suspect they're the ones right at the "top end" of this category, the people who are almost into the next category up. Here's what I think is going on:

The "difficulties" group and the "none" group are essentially the same in terms of the levels of crap stuff happening to them - because they are the same, normal, everyday people - except that a small % of the "difficulties" group do have some moderate degree of problems, because they are close to being "PD". This does not mean that the "difficulties" category is a sensible one. Quite the reverse, it means it's rubbish, because it spans so many diverse people and lumps them all together. What you should do, if you insist on drawing lines in the sand, would be something like this:

Now I don't know that that's how things work, but it seems plausible to me. To be fair to the authors, this is not the only argument in their paper. Their basic point is that personality disturbance is a spectrum: rather than it being a black-and-white question of "normal" vs."PD", there are degrees, ranging from "simple PD" which is associated with a moderate degree of life crap, up to "complex PD" which has much more and "severe PD" which is worst of all. They suggest that in the upcoming DSM-V revision of psychiatric diagnosis, it would be useful to formally incorporate the severity spectrum in some way - unlike the current DSM-IV, there everything is either/or. They also argue that with more severe cases of PD, it is not very useful to assign individual PD diagnoses (DSM-IV has no less than 10 different PDs) - severe PD is just severe PD. That's all fine, as long as it doesn't lead to pathologizing 78% of the population - but this is exactly what it might do. The authors do admit that "the SCID screen for personality disorder, like almost all screening instruments, over-diagnoses personality pathology", but they provide little assurance that a "spectrum" approach won't do the same thing.

Yang M, Coid J, & Tyrer P (2010). Personality pathology recorded by severity: national survey. The British Journal of Psychiatry 197, 193-9 PMID: 20807963