Terms like "bipolar", "autistic" and "schizophrenic" are often used in jest to describe character traits. But how harmful is it to bandy the names of such conditions about?
It's a common form of hyperbole.
The neighbour who keeps his house tidy has Obsessive Compulsive Disorder (OCD). A socially awkward colleague is autistic. The weather isn't just changeable, it's bipolar.
Such analogies are so familiar they surely qualify as cliches. They are also inaccurate and, to many, deeply offensive.
Campaigners are targeting what many say is an increasingly common practice - deploying the language of clinical diagnosis to describe everyday personality traits.
Using these terms metaphorically is just a joke, not to be taken seriously, argue some. Others, however, warn that this serves to further obfuscate conditions that are widely misunderstood and stigmatised.
Either way, you don't have to look hard for evidence of such terminology being deployed in this manner - even from sources you might not anticipate.
In December 2010 the Observer newspaper apologised for describing TV presenter Gok Wan's dress sense as "schizophrenic". The International Monetary Fund's September 2011 World Economic Outlook, characterised a volatile global economy as "bipolar". In an article for the Sunday Times, the writer Robert Harris described Gordon Brown and Richard Nixon as displaying "political Asperger's syndrome".
The mental health metaphor also has the distinction of having been deployed by that noted savant of the English language, Katie Price. During a court appearance in which she insisted she had been spraying scent rather than using her mobile phone while driving, the glamour model said: "I am quite OCD about my perfume habits, all my friends know that I'm always spraying perfume."
Research suggests these are far from isolated examples. A 2007 study of the terms "schizophrenia" and "schizophrenic" in the UK national press found that 11% of references were metaphorical, with broadsheet papers more likely to deploy such phrasing than tabloids. By contrast, cancer was only used in this manner in 0.02% of cases.
If anything, the UK is less prone to this tendency than other developed nations. Separate surveys in the United States, Germany and Switzerland found respectively that 28%, 58% and 31% of references to the condition were metaphorical.
Nonetheless, Arun Chopra, a consultant psychiatrist at Queen's Medical Centre in Nottingham and the author of the British research, believes the tendency has a negative impact on the treatment of patients.
He argues that deploying terms in such a way contributes to public misunderstanding - for instance, reinforcing the false notion that schizophrenia is a "Jekyll and Hyde" illness related to split personalities.
Moreover, he says it can be deeply upsetting to patients and their families, and recalls seeing a woman whose son was diagnosed with the condition bursting into tears when she read a newspaper article which described the weather as "schizophrenic".
"The use of the word as a metaphor is tremendously damaging," Chopra adds. "It's part of the process of creating a stigma around mental illness.
"You would never hear it used in relation to a physical condition. You wouldn't hear someone being described as a bit diabetic."
As such, he says he would like the Oxford English Dictionary to remove its secondary definition of schizophrenic: "With the implication of mutually contradictory or inconsistent elements".
Of course, deploying medical language to describe character traits is hardly a new phenomenon. Words like cretin and lunatic were originally formal terms to describe specific conditions before they more commonly came to be used pejoratively.
However, not all those affected by frequently misapplied conditions object to their use in this manner.
The Daily Telegraph columnist Bryony Gordon, who has been diagnosed with OCD, says she frequently has to point out that her disorder involves more than simply cleaning her house.
But she feels that attempting to clamp down on this kind of use of the term veers close to political correctness - and, moreover, that she is grateful the condition is, at least, widely discussed.
"It doesn't offend me when people trivialise it," she says. "It's almost a vehicle to talk about it.
"In a way it's a good thing because people acknowledge it exists. You're stuck in your own head and to see other people making light of something makes you think, 'Ah, this is what's happening.' It makes you feel better about it."
Most advocates for such conditions disagree, however.
Andrew McCulloch, chief executive of the Mental Health Foundation, argues that using a clinical diagnosis to describe minor personality traits can only serve to fuel misunderstanding.
"The upside is that we have moved on from a fear of mentioning these things at all, but it is a tiny step forward," he says. "The trouble is these terms all come to mean the same thing. Then they become as unpleasant as describing someone with schizophrenia as a lunatic.
"The reality is we still have a long way to go when it comes to educating people about mental health. People might use these terms more frequently now but the stigma of having a mental illness is as bad as it has ever been."
Still, attempts by some mental health service users to reclaim pejorative labels under the banner of so-called "mad pride" demonstrate that there is unlikely to ever be consensus about the best way to respond.
The flippant use of such terms nowadays may offend some and not bother others. But such a dynamic is part of the words' evolution, says Joel Rose, director of OCD Action.
"Five years ago people wouldn't have known what you were talking about if you mentioned OCD," he says. "Now they have a sense of what it is about and use it, but don't really fully understand it. The next five years will be about working to fully educate people.
"What we want people to understand is how serious and debilitating OCD can be. We're talking about people who might clean a floor repeatedly for eight hours or someone who can't leave the house. It's not having a tidy house or arranging the tins of food in your cupboard. We also want to get across that it is treatable."
Indeed, many of those diagnosed with the condition have successfully learned to manage it. Overcoming its metaphorical use, however, may prove more difficult.