Going to the loo without a book! It is a profound shock. Instead of reading, I stare at the walls and notice that there are still two empty nails on which I meant – a year ago – to hang pictures. Also, I notice the dust on the floor and the cobwebs on the ceiling. I sense that I will be doing a lot more housework than usual this week.

Going to bed is bizarre. If there is one time of day I always, always read, it is in bed before I go to sleep. On the first night of my week without books, I download Being Human on the iPlayer and give my nail polish some quality attention. But when the programme finishes and I try to shut my eyes, my head is buzzing. My eyes keep bouncing open again. Boing. Boing. Boing.

I decided to try giving up books for a week because I have come to the point where I wonder if they are holding me back. On the whole, the world seems to think that books are always a good thing, that you can never get too much of them. People admit to being bookworms in the same way they admit to being "just too tidy really", or "a bit of a workaholic". But if you are a compulsive reader like me, who reads walking down the road, and while she's making her children's dinner, and on the loo and in the bath and in bed and on the bus, and at every other possible second of the day, and if what you're reading is mostly . . . well . . . pulp, then sometimes you end up feeling as if books are eating you up instead of the other way round. Sure, there's a smattering of literature and high art-type stuff in there, but mostly it is whatever I have fished off the shelf at my nearest Oxfam that morning – detective stories, romances, horror, sci fi . . . any kind of fiction that I can gulp down in large enough, quick enough bites.

I am usually reading three, sometimes four books, with a pile of books waiting in case I run out. I never leave the house without my book, and if I'm taking a train I'll usually have a back-up book in case I finish the first one. I'd rather read than do housework or laundry, and sometimes I'd rather read than talk to friends or husband or family. I've been known to boot my children off out into the garden or switch on the TV – "or anything, just sod off for 10 minutes!" – so that I can finally be alone with my book; worse still, I regularly succumb to the siren call of the current novel when I am supposed to be working.

This problem, you would think, could be simply dealt with by giving up reading books. So out of pure curiosity I do. And by Tuesday, after the first day of feeling very odd indeed, I begin to think that I'm getting the hang of this. Instead of reading, I make notes for work, or read the papers, or tidy the kitchen. During a train journey up to London in the afternoon, I open up my laptop instead of snuggling into my chair with my book. I feel quite purposeful, actually, as if I am concentrating properly on my life, instead of wishing it away so that I can get to my book.

On Wednesday, I get myself some breakfast after doing the school run. Instead of eating hunched pleasurably over a book, I look out of the window and chew every mouthful thoroughly, aware of every single oat and nut and dried bit of apple as it goes down. When the children get home with some friends, I end up doing some colouring-in instead of skulking in the kitchen making their dinner with a book in my hand. The part of me that has always sneakily wondered if life might not be simpler and more straightforward without these excursions into fictional worlds is going, "You see? You see?".

But the rest of me is missing books like a drug, to the extent that I start to wonder if it actually is some kind of drug. The odd thing is that when I try to find out more about it, about whether reading fiction produces some kind of hormone in your mind, no one seems to know. Robert Darnton, director of the Harvard Library and a specialist in the history of the book, tells me: "Reading is mysterious, and we don't really understand how it is that we make sense of these signs that are embedded in paper or on computer screens. There have been attempts by cognitive scientists to measure the chemical exchanges in the brain, but as far as I can tell no scientist has really fully explained it. They're working on it."

So we don't know exactly what is happening, how the piles of pages or markings on the screen are transformed into other worlds inside our minds. But we do know that our brain experiences what the characters we are reading about experience. In a book coming out next year about the psychology of fiction, Professor Keith Oatley describes a piece of research where scientists got people to read while they were in a brain scanner. "When readers were engaged in a story, the researchers found that, at the points in which the story said a protagonist undertook an action, the part of the brain which was activated was the part which the reader himself or herself would use to undertake the action. So, when the story- protagonist pulled a light cord, a region in the frontal lobes of the reader's brain associated with grasping things was activated."

The fact is that in evolutionary terms, reading in an escapist way is a very recent human activity, nothing like as traditional a method of self-medication as drink, say, or even drugs. For most of our history, reading has been done by just a few specialists, and aloud. In the fifth century, Saint Augustine was famously perplexed by the weird habits of Saint Ambrose: "When he read, his eyes scanned the page and his heart sought out the meaning, but his voice was silent and his tongue was still. Anyone could approach him freely and guests were not commonly announced, so that often, when we came to visit him, we found him reading like this in silence, for he never read aloud."

It wasn't until more than a thousand years later, and with the invention of the novel, that it became more common to read silently to yourself, and also that it began, as an occupation, to worry the authorities. In Germany in the 18th and 19th centuries, "reading epidemics" swept the country. In France, certain novels were considered a threat to the state, and censored; some authors were even murdered. In England, general contempt for novels led Jane Austen in Northanger Abbey to come out of character briefly to passionately defend her fellow novelists whose "productions have afforded more extensive and affected pleasure than those of any other literary corporation in the world" but whose "foes are almost more than our readers".

And reading has not gone away. The grip of fiction on the public has continued to grow and grow, and now books are seen as a far healthier alternative to TV or computer games. They continue to be devoured by a public, who bought 235.7m books in the UK in 2009, and who are not stopping buying books despite the economy (sales only fell by 0.5%). "We read more during recessions," says Darnton. "During the Great Depression, the Chicago public library was filled with readers, and I'm pretty sure you'll find the same is true now. It's an escape from stress."

Ah yes, stress. By Thursday, my early glow has worn off after a long day coping with winter, an ill parent, one particularly grumpy son, and the general detritus of life. I am incredibly tetchy and snappy; more than usual? Impossible to know (everyone's too scared to tell me), but Friday is the same and even a little worse and I can't find any way to relax, to switch off and get away from the things that you list in your head at 11.30pm at night. After school on Friday evening, when the boys have had tea and watched a bit of TV, they racket off downstairs for a game of hide and seek, and I slump down on to the sofa for a half hour that would usually involve a novel, a cuppa, and maybe a biscuit. Instead, after staring at the wall for a bit, I fetch my laptop and do some more work. Life feels deeply, wintrily joyless. It feels wall-to-wall grey.

Books, I realise, have been one of my longest, truest friends. When I'm anxious, sad, angry, in need of comfort, a book is often the first place I will go: I even have books that I regularly re-read when I'm feeling particularly awful (can I just recommend the Bitch in the House if you've been a particularly bad mother that day?). And now I have just cast them aside, as if all my flaws are their fault, and not the other way round.

The day that the ban is lifted, I wait until the children have gone to bed, and then pick up the novel I was halfway through when the axe fell, pour a glass of wine and settle down with it, a bit worried that somehow (like the first puff of a fag when you've given up smoking for a while) it won't be as good as before, that somehow I will have spoilt it.

But there's no need to worry. Immediately, it is as if the wardrobe doors to Narnia have been thrown open again and thousands of other technicolour lives have tumbled straight back out from that eighth dimension inside my head. Day-to-day life just fades out, I stop worrying, stop twitching and just forget who or where I am for a gorgeous hour. I have still not got around to hanging those pictures in the bathroom. But reader, I am never giving up books again.