Name: 47.2.

Age: 47.2.

Appearance: Grumpy.

Age is just a number. Yes, in this case the worst number possible.

The worst number for what? For wellbeing. According to a study from the US’s National Bureau of Economic Research, 47.2 is the unhappiest age you can be.

What happens after that? You start to feel a bit better.

You mean people in their 50s are happier than people in their 40s? Yes, and people in their 60s are happier still.

Why on earth would that be? No one can say for sure, but traditionally the idea is that the pressures and anxieties of work and family increase throughout your adult years until you hit your mid-40s, and then they begin to abate. Happiness correspondingly dips and recovers.

First-world problems. That’s what people used to think, but this new study, produced by the former Bank of England economist David Blanchflower, examined data across 132 countries, and found that the happiness curve is similarly U-shaped everywhere.

So 47.2 is the global age of maximum unhappiness? It strikes a bit later – at 48.2 – in the developing world, but the pattern remains the same. “The curve’s trajectory holds true in countries where the median wage is high and where it is not, and where people tend to live longer and where they don’t,” writes Blanchflower.

Does this mean that midlife misery is genetic? It could well be that we are hardwired for it. A 2012 study of chimpanzees and orangutans found that apes also have a midlife happiness low-point, at about the age of 30.

Happiness is a subjective concept. How do you measure how miserable people are for the purposes of a scientific study? It depends on the country, but in the UK, for example, the Annual Population Survey sums it up in a question.

Which is? “Overall, how satisfied are you with your life nowadays?”

Oh, God, don’t get me started. No, I wasn’t asking you that. I was just …

I’m massively in debt, my kids hate me, my boss is an idiot and Boris Johnson is the prime minister. How satisfied should I be? I suppose we all have our difficulties.

Is that right? Have you seen this rash on my chest? The doctor says it’s stress. Well, if there are no further questions on the topic …

Wait, I do have one more: how do you ask a chimp how happy it is? You ask the zookeepers.

Do say: “Hang in there, baby – 47.3 is coming.”

Don’t say: “Relax – it’s all uphill from here, and then you die.”