I finally got round to seeing Split, the M. Night Shyamalan film (spoilers follow) about a problematic case of split personality, and while it’s quite a gripping film with a bravura central performance from James McAvoy,  I couldn’t help feeling that in various other ways it was somewhere between unhelpful and irresponsible. Briefly, in the film we’re given a character suffering from Dissociative Identity Disorder (DID), the condition formerly known as ‘Multiple Personality Disorder’.  The working arrangement reached by his ‘alters’, the different personalities inhabiting an unfortunate character called Kevin Wendell Crumb, has been disturbed by two of the darker alters (there are 23); he kidnaps three girls and it gradually becomes clear that the ‘Beast’, a further (24th) alter is going to eat them.

DID has a chequered and still somewhat controversial history. I discussed it at moderate length here (Oh dear, tempus fugit) about eleven years ago. One of the things about it is that its incidence is strongly affected by cultural factors. It’s very much higher in some countries than others, and the appearance of popular films or books about it seems to have a major impact, increasing the number of diagnoses in subsequent years. This phenomenon apparently goes right back to Jekyll and Hyde, an early fictional version which remains powerful in Anglophone culture. In fact Split itself draws on two notable features of Jekyll and Hyde: the ideas that some alters are likely to be wicked, and that they may differ in appearance and even size from the original. The number of cases in the US rose dramatically after the TV series Sybil, based on a real case, first aired (though subsequently doubts about the real-world diagnosis have emerged). It’s also probable that the popular view has been influenced by the persistent misunderstanding that schizophrenia is having a  ‘split personality’ (it isn’t, although it’s not unknown for DID patients to have schizophrenia too: and some ‘Schneiderian’ symptoms – voices, inserted thoughts – may confusingly arise from either condition.

One view is that while DID is undeniably a real mental condition, it is largely or wholly iatrogenic: caused by the doctors. On this view therapists trying to draw out alters for the best of reasons may simply be encouraging patients to confabulate them, or indeed the whole problem. On this view the cultural background may be very important in preparing the minds of patients (and indeed the minds of therapists: let’s be honest, psychologists watch stupid films too). So the first charge against Split is that it is likely to cause another spike in the number of DID cases.

Is that a bad thing, though? One argument is that cultural factors don’t cause the dissociative problems, they merely lead to more of them being properly diagnosed. One mainstream modern view sees DID as a response to childhood trauma; the sufferer generates a separate persona to deal with the intolerable pain. And often enough it works; we might see DID less as a mental problem and more as a strategy, often successful, for dealing with certain mental problems. There’s actually no need to reintegrate the alters, any more than you would try to homogenise any other personality; all you need to do is reach a satisfactory working arrangement. If that’s the case then making knowledge of DID more widely available might actually be a good thing.

That might be an arguable position, though we’d have to take some account of the potential for disruptive and amnesiac episodes that may come along with DID. However, Split can hardly be seen as making a valuable contribution to awareness because of the way it draws on Jekyll and Hyde tropes. First, there’s the renewed suggestion that alters usually include terrifically evil personalities. The central character in Split is apparently going to become a super-villain in a sequel. This will be a ‘grounded’ super; one whose powers are not attributable to the semi-magic effects of radiation or film-style mutation, but ‘realistically’ to DID. Putting aside the super powers, I don’t know of any evidence that people with DID have a worse criminal record than anyone else; if anything I’d guess that coping with their own problems leaves them no time or capacity for  embarking on crime sprees. But portraying them as inherently bad inevitably stigmatises existing patients and deters future diagnoses in ways that are surely offensive and unhelpful. It might even cause some patients to think that their alters have to behave badly in order to validate their diagnosis.

Of course, Hollywood almost invariably portrays mental problems as hidden superpowers. Autism makes you a mathematical genius; OCD means you’re really tidy and well-organised. But the suggestion that DID probably makes you a wall-climbing murderer is an especially negative one.  Zombies, those harmless victims of bizarre Caribbean brainwashing, possibly got a similarly negative treatment when they were transformed by Romero into brain-munching corpse monsters; but luckily I think that diagnosis is rare.

The other thing about Split is that it takes some of the wilder claims about the physical impact of DID and exaggerates them to absurdity. The psychologist in the film, Dr. Karen Fletcher merely asserts that the switch between alters can change people’s body chemistry: fine, getting into an emotional state changes that. But it emerges that Kevin’s eyesight, size and strength all change with his alters: one of them even needs insulin injections while the others don’t (a miracle that the one who needs them ever managed to manifest consistently enough to get the medication prescribed). In his final monster incarnation he becomes bigger, more muscled, able to climb walls like a fly, and invulnerable to being shot in the chest at close range (we really don’t want patients believing in that one, do we?). Remarkable in the circumstances that his one female alter didn’t develop a bulging bosom.

Anyway, you may have noticed that Hollywood isn’t the only context in which zombies have been used for other purposes and dubious stories about personal identity told. In philosophy our problems with traditional agency and responsibility have led to widespread acceptance of attenuated forms of personhood; multiple draft people, various self-referential illusions, and epiphenomenal confabulations. These sceptical views of common-sense selfhood are often discussed in a relatively positive light, as yielding a kind of Buddhist insight, or bringing a welcome relief from moral liability; but I don’t think it’s too fanciful to fear that they might also create a climate that fosters a sense of powerlessness and depersonalisation. I’d be the last person to say that philosophers should self-censor, still less that they should avoid hypotheses that look true or interesting but are depressing. Nor am I suffering from the delusion that the public at large, or even academic psychologists, are waiting eagerly to hear what the philosophers think. But perhaps there’s room for slightly more awareness that these are not purely academic issues?