Is the British Stiff Upper Lip killing us? That theory was put forward this week in the British Journal of Cancer by researchers looking into why the British are less likely to report symptoms than other Europeans – and therefore less likely to survive cancer. The problem, the lead researcher Dr Lindsay Forbes suggests, may be that "we are more stoic and have a war-time mentality". This foray into the national psyche comes just weeks after Dr Phillip Lee, a GP and Tory MP, suggested that the NHS was buckling under the strain of hypochondriac baby-boomers, who lacked the "stoicism" of their "parents who survived the war".

A recent YouGov poll found us just as divided and confused: 57% thought we no longer have a national stiff upper lip, while 57% also believed we are less prone to emotional displays than other nationalities. Clearly, the stiff upper lip remains a part of the national persona, whether we think it survives or has been fatally lost.

It wasn't always thus. In the 18th century the English were seen by other Europeans and ourselves as a nation of highly strung hysterics, prone to nervousness, melancholy and suicide, all classic symptoms of the English malady.

It was only in the late 19th century that we started to pride ourselves on our stoicism. As my boss at the Centre for the History of the Emotions, Thomas Dixon, has explored, the main drivers for this were science and imperialism. In 1872 Charles Darwin's The Expression of Emotions in Man and Animals put forward a racial hierarchy, in which "savages weep copiously from very slight causes" while "Englishmen rarely cry, except under the pressure of the acutest grief". Likewise, men were supposed to be less emotional than women, and the upper classes less emotional than the lower.

This idea was used as ideology as we colonised other nations and races: our right to govern others was founded on our supposedly superior ability at governing ourselves. The myth survived into the second world war and morphed into the "blitz spirit", the cheery Anglo-Saxon phlegmaticness we contrasted with Hitler and Mussolini's hysterics.

The standard history goes that the stiff upper lip disappeared in the 1960s, amid the decline of the empire, the age of affluence, and the wailing of Beatlemania. With the popularisation of psychoanalysis, the stiff upper lip came to be seen as uptight, and repressed. By the 1990s even our national footballers sobbed, and stoicism was increasingly seen as pathological. In 1995 Liverpool University's psychology department launched a "stoicism scale" that measured people's refusal to discuss their emotions – a trait that some suggested was correlated with suicidal tendencies.

I personally left school in the mid-1990s with the wrong kind of stoicism. Suffering from depression at university, I hid it from my friends and family out of a misplaced sense of masculine pride. After several years of quiet desperation, I was helped by a support group that offered cognitive behavioural therapy. We sat in a circle discussing our feelings in a very un-British way.

CBT, I later discovered, was actually inspired by the ancient Stoics, who turned out not to be emotionally repressed at all. In fact, their writings on the emotions "have a cogency unsurpassed by anything on that topic in the history of western philosophy", according to Martha Nussbaum, the great modern philosopher of the emotions. The Stoics didn't believe in suppressing your emotions, but instead in understanding how your beliefs gave rise to them, and how you could change your beliefs in order to change your emotions. You did this not for public display (the Stoics didn't care about the approval of others) but simply because it made your life better.

CBT and other talking therapies are now widely available on the NHS, and as a nation I would suggest we are increasingly emotionally intelligent and capable of talking about our emotions and mental health. Some critics complain that our "therapy culture" has made us less Stoic. But to me the mass availability of CBT is making us more Stoic, not less.

I still meet many people who suffer in silence, who won't discuss their emotional problems with friends or family out of fear of being thought weak or degenerate. The old myth of the stiff upper lip still has cultural power and, as this latest study suggests, it can cause us real harm. Being Stoic doesn't mean repressing your feelings – it means understanding them and learning to take care of yourself.