Can a Lack of Sleep Really Drive You Mad?

How long could you manage without sleep? The current record-holder is Randy Gardner, who as a 17-year-old Californian high-school student back in 1964 managed a staggering 265 hours -- or 11 days -- without so much as a nap.

"I wanted to prove that bad things didn't happen if you went without sleep," Gardner explained. In fact, by the time he finally broke the record, Gardner had endured crippling exhaustion, forgetfulness, dizziness, slurred speech and blurred vision. He'd been moody and irritable, and unable to concentrate on the simplest tasks. He'd even experienced hallucinations and delusions (on one occasion, for instance, imagining that he was the legendary San Diego Chargers' running back Paul Lowe). "We got halfway through the damn thing and I thought, ‘This is tough. I don't want to do this any more,' " Gardner recalled in 2006. "But everybody was looking at me so I couldn't quit."

Of course, you don't need to have made an attempt on Randy Gardner's record to know that lack of sleep can have some pretty unwelcome consequences. Anyone who has ever had to suffer a sleepless night will know just how disruptive it can be. The following day we're tired, irritable, a little miserable, and generally out of sorts. And the longer sleep problems go on, the more wretched we feel.

The consequences don't end there. It's long been known that people with psychological problems such as anxiety, depression, paranoia, bipolar disorder, and attention-deficit hyperactivity disorder (ADHD) don't sleep well. Until recently, it was assumed their sleep difficulties were a product of the psychological problem. But research suggests that the process may also work in the opposite direction: persistent sleep problems may help cause and exacerbate a number of common mental illnesses.

The clinical definition of insomnia is taking longer than 30 minutes to fall asleep on several nights each week and over at least a month, which causes problems in daytime functioning. One recent Keele University study of more than 2,500 people in Staffordshire found that individuals with insomnia were nearly three times more likely to develop depression over the next 12 months and more than twice as likely to suffer from anxiety. And research in the US has suggested that people with breathing-related sleeping disorders such as sleep apnoea (in which breathing stops for a few seconds) are at greater risk of developing depression -- and the worse the sleep problem, the more likely it is that they'll become depressed.

Disturbed sleep is a well-known early sign of the manic episodes that characterise bipolar disorder (what used to be termed "manic depression"). Now there's evidence that these sleep problems aren't simply a symptom of the illness; they can also trigger the manic episodes.

A similar picture emerges from research we carried out recently at the Institute of Psychiatry, King's College London into the links between insomnia and paranoia. When we assessed 300 members of the general public, we found that those suffering from insomnia were five times more likely to experience strong paranoid thoughts than those who generally slept well. Part of the explanation for this startling statistic, we believe, is that insomnia is helping to cause paranoid thoughts, much as it can do for depression or anxiety.

The link between sleep problems and psychological problems isn't confined to adults. A |number of studies indicate that children who don't get enough sleep are prone to the sorts of behavioural problems that can look like the signs of ADHD. Earlier this year Finnish researchers published the results of a study of 280 seven- to eight-year-olds. The children who slept fewer than 7.7 hours a night were more prone to hyperactivity, restlessness, impulsiveness and lack of concentration.