Although not due to be published until May 2013, the fifth edition of the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) is already provoking dissent among psychiatrists and psychologists in Britain. Critics claim it will make an already problematic diagnostic system worse and result in more people being labelled mentally ill.

Producing a new edition of the DSM is a major undertaking. This one, prompted by the accumulation of new information on neurology, genetics, and behavioural sciences, has been compiled by the 162 members of 13 separate work groups, helped by a further 300 advisors and informed by …