So, according to the economists David Blanchflower and Andrew Oswald, middle aged people the world over are most likely to be depressed between the ages of 40 and 50. I'm definitely depressed to hear that I'm "middle-aged", at 41, but prior to that I was very happy.

I just don't recognise the "U shape of happiness" they have described; that we basically start and end happy and feel rubbish in the middle. My early childhood was probably happy, though I can't remember it much. Being a teenager must be the worst phase of all though; can any mid-life crisis compete with the unremitting existential nightmare of those six long years? Life is out there, being lived by other people, and you're stuck with what beauty counter sales assistants would discreetly call combination skin. The very worst part of being a teenager is that unholy mix of simultaneously lacking self-confidence, and being completely obsessed with yourself.

Once we hit our 20s and 30s and stop comparing ourselves to our peers though, things can really pick up. Disappointments and humiliations still come thick and fast, of course; I don't think I ever left a job voluntarily. And trying to find a boyfriend was worse; I remember going on a date with a poetry reciting, medicated, tee-totaller and the only question he asked me during our dry, l-o-n-g lunch was: "Tell me what you do, but don't go on about it." But I got more resilient and realised depressing incidents were nothing more than anecdotes to tell my friends.

I don't agree that as we get older we quell our unfeasible aspirations, we just find out what they truly are. Of course I don't want to be Sheryl Crowe and scream "THANK YOU NEW YORK!!" to a capacity crowd at Madison Square Garden. But I actually want to be productive (big surprise, I always thought I was bone idle), to have love, to buy Jonathan Kelsey cone heels, binge-drink, laugh at my friends, have better relationships all round, eat bacon sandwiches and never set foot in a museum. Reality sets in but that's good; slowly you realise what you don't like doing, and try and do less of it and understand what makes you happy, and try and do more of it.

This is not to sound smug at all. I'm a late bloomer (I didn't even snog a boy till I was 16) so I'll probably hit my middle-aged depression just as everyone else my age is coming out of theirs.