Ten to eleven

It's a Tuesday night, ten to eleven. You're in bed with the light off, and the muscle in your left calf is twitching. It's a small flutter under the skin, a few seconds at a time, and it's been doing it on and off since the weekend.

You pick up the phone from the bedside table and type "calf muscle twitching". The first result is from the NHS. It says twitches are common and very rarely a sign of anything serious. It says they're often linked to stress, tiredness and caffeine. You had three coffees today, and you've been sleeping badly for a fortnight.

It's a full explanation, and you don't take it. You scroll down to the section headed "Conditions that can cause a twitch", and then you go back to the results and open the next one, and the one after. By twenty past eleven you've learned the name of a rare disease of the nerves. By midnight you're on a forum for people who have it, reading a post by a man whose first sign was a twitch in his calf.

At twenty to one you go to the bathroom, shut the door quietly, and stand on tiptoe on your left leg to see whether it's weaker than your right. You can't tell. You try again, and it might be. You go back to bed and lie awake, and the calf twitches, and each time it does your stomach turns over.

In the morning you're exhausted. The fear has shrunk to a manageable size in daylight, and you feel slightly foolish. By Thursday night you're searching again.

I'll use a few terms throughout. The search is a whole session, from the first query to the moment you put the phone down. The first answer is the ordinary explanation that usually turns up early on, which you read and pass over. The frightening answer is where the search ends. Checking means testing or examining your own body for signs, like the tiptoe in the bathroom. The dip is the short spell of relief you sometimes get from a reassuring page or a reassuring person. And the one look is what I'll suggest in place of the search.

The search has some regular features. This list is my own observation and not a research finding.

It starts with a real sensation. You aren't imagining the twitch.

It happens late and alone, and nearly always on a phone.

It passes over the first answer. The ordinary explanation is read, understood and not accepted, and the reading goes on.

It moves in one direction. Searches go from common to rare and from mild to grave, and almost never the other way.

It ends at the frightening answer. The search usually stops at the worst thing found, or when you're too tired to go on.

And it changes how you behave afterwards. You check your body, you sleep badly, and the next search starts sooner.

Try one thing before reading on. Open your browser history and look at the last month. Count the searches about symptoms, and roughly how long each went on. Next to each, write how you felt afterwards, in a word. If most of them say "fine" or "relieved", searching may be working well for you, and you may not need this book. If most of them say "worse", read on. You can adopt chapter 15's way of handling a symptom today if you like. There's no need to finish the argument first.