Sherlock Holmes is famous for his sharp wit, reclusive nature, powers of observation and talent for deduction. To this list the modern-day BBC adaptation of Conan Doyle's stories has added ‘Asperger's’ – or its DSM-5 term: autism spectrum disorder (ASD).

A throwaway comment from Dr Watson, Sherlock's friend, full-time ‘assistant’ and, importantly, a doctor, adds fuel to a long-standing online debate over whether the detective (as well as other fictional characters in popular media) has autism. Although psychiatrists might consider it inappropriate and unhelpful to ‘diagnose’ a fictional character based on their fictitious behaviour in a television show, the general public (and indeed screenwriters) are less hesitant to draw parallels with their own experiences and observations of psychiatric illnesses.

In some ways, labelling a character with ASD has become a dramatic plot device to inject new life into the old archetype of the antisocial flawed genius. The diagnosis is commonly used to explain a character's ‘one track’ mindset, their unusual expertise in niche subjects being presented as a ‘special interest’. In Holmes' case, such an association is not unsubstantiated: his crime-solving pursuits do have many of the qualities of a ‘special interest’ in terms of their intensity and focus. They occupy most of his time to the exclusion of other everyday activities including eating and sleeping, and do seem to inspire something akin to the ‘overwhelming excitement’ that those with ASD describe – such that he finds it difficult not to talk about his deductions even when the setting is socially inappropriate or his audience uninterested. And while his deductions seem initially astounding, when explained step-by-step they seem ordinary, obvious even, remarkable only for his unusual allocation of attention to details others have overlooked and his extensive knowledge of forensic subjects. We might even speculate that Sherlock's talent for deductive reasoning could have developed out of a desire to ‘solve’ intellectually, from physical clues, the people and relationships he struggled to understand intuitively, from social ones.

The other trait commonly ‘explained’ using the ASD label is difficulties with social interaction and communication, also present in Holmes: difficulties with adjusting his behaviour to social context, decreased social reciprocity and a reduced interest in forming friendships. However, these are not significant enough to have prevented him from maintaining several lasting friendships. Nor does he have any impaired understanding of non-verbal communication and his own communication is rich and complex. In fact, fundamental to Sherlock's success as a detective is his aptitude for identifying and understanding others' emotions and motivations. He frequently manipulates and lies persuasively to obtain information, a behaviour requiring significant social-communication skills to carry out successfully. Indeed, by yoking this reincarnation of Sherlock Holmes to autism, the writers appear to conflate their character's voluntary disregard for the feelings of others and contempt for social niceties with the genuine difficulties in social communication and empathy seen in people with autism. This demonstrates a disregard for that all-important component of any detective story: motive.

Just as medical dramas can influence health-seeking behaviours, unjustified use of psychiatric labels can perpetuate harmful misrepresentations – yet whose responsibility is this? For writers, the priority is entertainment over education; for psychiatrists, real, not fictional, patients.

The opening quote comes from the BBC series Sherlock (season 2, episode 2: ‘The hounds of Baskerville’, first aired in the UK on 8 January 2012).