When you lose your temper in your pyjamas, there's no dignity. It was three o'clock in the morning and I had just been woken up for the second time, on my fourth consecutive night of broken sleep.

My producer, Natalie, was trying to persuade me to do another piece to camera about how I was feeling. "What's the point?" I squawked, my face screwed up in resentment. "I've got nothing more to say. Why are we doing this anyway? I'm going to look so stupid."

Exhausted herself, but ever the professional, Natalie tried to reason with me. We were making a television documentary and we were doing this to try to give the viewers an insight into the effects of insomnia. I never usually lose my temper and Natalie had been a colleague and friend for nearly 10 years, but I didn't care any more. Lack of sleep meant that I had lost the awareness of the effects of my behaviour on other people. So I stood by my bed, like a cross between Andy Pandy and Kevin the Teenager: weepy, intransigent and incredibly annoying.

It had been a strange, difficult week, emulating the sleep pattern of an insomniac. Experts at the Glasgow Sleep Centre in the city's university had given me five envelopes – I was to open one each evening to discover my sleep timetable for that night. Typically, I would have to lie in bed awake for at least an hour before going to sleep, with my alarm set to go off at least twice during the night. When the alarm sounded, I would have to get out of bed and stay awake.

Natalie was waiting in the living room of the flat we rented to make sure I stuck to the plan – and the cameraman filmed me as I stared at the television. When I returned to bed, it was often only to watch the minutes tick towards the next alarm. As I was finding out, it's difficult to sleep to a schedule and I was miserable and anxious about having to get up again.

To try to gauge the impact of sleeplessness, I spent my days waiting on tables in a busy cafe in Southside, Glasgow. Monday was OK, I just felt a bit tired, but as the week wore on everything became more difficult. I really had to concentrate hard to do simple things.

Customers had to tell me what they wanted twice, because of the holes in my short-term memory. The till started to intimidate me – bleeping and flashing at my failure to get things in the right order as the numbers began to float around the screen. As well as becoming phenomenally grumpy, I'd developed a huge sense of foreboding – convinced that finding people a table and giving them a menu would be utterly beyond me.

One of the mantras at the sleep centre is that insomniacs don't have problems sleeping, they have problems living. My problems were beginning to mount up. My feet hurt when I walked, there was an ache in my back and I had a constant shivery feeling. At least when I was taking orders and serving food I had something to concentrate on – the rest of the time I felt a weird sense of alienation, like I was a visitor to the world. Normal life was something I was looking at, not taking part in. On Thursday I had a pathetic urge to ring a loved one and whinge at them, but I didn't because of a fear that they wouldn't know who I was. Very odd.

There were people at the cafe who knew how I was feeling. The catering industry is hard work and runs on unsociable hours. The cafe's owner, Paul, had suffered from insomnia since his teenage years. "I managed three hours last night," he would cheerfully report. But his face had a weary, resigned look.

Paul organised his working life around his sleeplessness – he would only do his invoices on a Tuesday morning, because he'd worked out that was the time in the week when he was most awake. His wife, Catherine, confessed to occasionally getting impatient with him. She used to be a good sleeper, she told me, but hadn't slept properly since their little girl was born a few years ago. "You just get on with it," she said.

The research says insomnia is becoming more common and the anecdotal evidence from the cafe seemed to bear that out. Many of the customers who asked me why I was being filmed were quick to recount their own sleep problems. One woman reached into her handbag to show me the sleeping pills she'd just picked up from the chemist.

Ten million sleeping tablets are prescribed in the UK every year. If we are failing to deal with the problem of insomnia, it's not because the health service doesn't know about it.

I wouldn't describe myself as a really good sleeper. Like most people, the anxieties and aspirations of modern life can keep me awake. In my work as a reporter for ITV News I sometimes find myself in war zones or disaster areas where I go for a few days without sleeping properly.

At home, though, sleepless nights are thankfully rare. When I do have one, there is usually a good reason for it – I might be upset about something or have a big story to cover the following day. I am also lucky enough to regard my bedroom as a peaceful place – a refuge.

My week living as an insomniac taught me that, for those who suffer from chronic sleep problems, the night is something to fear and the bedroom is a place of torment. Psychologists talk about how it is crucial to have "trust" in sleep – the knowledge that when you lie down in bed, sleep will come. Insomniacs have lost that trust.

There are sometimes obvious triggers for insomnia, like trauma or bereavement, but the mysteries of the mind mean that scientists are a long way from identifying a common physiological factor. One we spoke to had discovered that some insomniacs suffer from a thinning of the cortex at the front of the brain – the part that senses comfort – and so signals aren't sent to the rest of the brain telling it that it's OK to switch off. Another said insomnia was caused by a malfunction in the suprachiasmatic nucleus – the "clock" in our heads that lets us know when it's time to go to sleep.

Whatever the cause, most experts agree that insomnia is a long-term psychological problem for which sleeping tablets provide only a short-term solution.

At the Glasgow Sleep Centre, where I spent my last sleepless night, there's frustration that insomnia isn't given the same priority by the NHS as other psychological disorders, such as depression. Researchers there are developing treatments based on cognitive behavioural therapy, relaxation techniques to calm the "racing mind" and help insomniacs to win back their trust in sleep. The science says CBT works and the government is spending a lot of money on making it available for the treatment of depression and anxiety, but not yet for insomnia.

For me, the sleep centre couldn't have been less aptly named. They wired me up to a monitor and bellowed at me through a loudspeaker system at various points during the night to make sure I woke up. It felt like torture.

In the morning, the printout showed what I already knew – I'd barely slept and the sleep I did get wasn't deep. It was the classic sleep pattern of an insomniac. The experiment was over. I felt wretched, but I had some understanding of how people who suffer from long-term sleep problems can underperform at work, have difficulty maintaining relationships and are more vulnerable to illness. In short, they may never reach their full potential.

I felt glorious heading into the office the following week, having had my energy restored by a few good nights' sleep. The thick fog around the edges of my mind had lifted. I could think clearly, stand up straight and be part of the world again. I started by buying Natalie some flowers.

"Waking Up To Insomnia: Tonight" will be screened at 7.30pm on Thursday 17 November, ITV1