‘The only clever word is yes.’ –Gilles Deleuze
Is mental illness good for you?
Mental illness is surprisingly common. About 10% of the population is affected by it at any one time and up to 25% suffer some kind of mental illness over their lifetime. This has led some people (many people in fact) to surmise that it must exist for a reason – in particular that it must be associated with some kind of evolutionary advantage. Indeed, this is a popular and persistent idea both in scientific circles and in the general public.
Such theories come in two main varieties – the first, that mental illness confers some specific advantage to those afflicted; and second, that the mutations which cause mental illness in one person’s genetic background may confer an advantage when they are in a different genetic background (balancing selection).
