What were you doing before you started reading this? Were you fully focused on another article? Or doing the crossword? Eating breakfast? Organising your day? Or were you staring out of the window, feeling restless and bored?

It is more likely to have been the latter. Fleeting moments of boredom are universal, and are often what drives us to stop what we are doing and shift to something that we hope will be more stimulating.

But although boredom is common, it is neither trivial nor benign, according to Dr John Eastwood, a psychologist at York University, Toronto. Eastwood is the joint author of The Unengaged Mind, a major new paper on the theory of boredom.

Boredom, he points out, has been associated with increased drug and alcohol abuse, overeating, depression and anxiety, and an increased risk of making mistakes. Mistakes at work might not be a matter of life and death for most of us, but if you are an air traffic controller, pilot or nuclear power plant operator, they most certainly can be.

Commercial pilot Sami Franks (not his real name) confirms that boredom can make pilots lose attention. "When you fly long haul, there are two pilots, one of whom is monitoring all the screens while the other does the paperwork, talks to air traffic control and so on. You need to be alert for landing and takeoff, but once you're 500ft above the runway, the plane's on autopilot and it can be very quiet and boring.

"In a study I saw of co-pilots who woke up after a nap, 30% reported seeing the other pilot asleep too," adds Franks, in a comment that will not play well with nervous flyers.

The stakes are not usually so high, but boredom can be protracted, heavy and associated with an unpleasant sensation, according to Eastwood. And despite having attracted the attention of philosophers, psychologists, neuroscientists and educationalists, there is no precise definition of boredom and no consensus as to how we counter it. The report says boredom is most often conceptualised as "the aversive experience of wanting, but being unable, to engage in satisfying activity."

"All instances of boredom involve a failure of attention," says Eastwood. "And attention is what you are using now to blot out the plethora of stimuli around you while you focus awareness on a given topic."

There are three functions involved in attention. We have to be suitably aroused, so as not to fall asleep on the job. Then we have an orienting system that can cut in so that if you cross the road, deep in thought, you will still respond to a flickering light on the edge of your visual field that heralds a fast-approaching car. And the third type of attention is an executive system that oversees our mental activities, so we can consciously stay engaged even if the task is not very interesting. Boredom results when any of these functions breaks down.

Dr Esther Priyadharshini, a senior lecturer in education at the University of East Anglia, has studied boredom and says it can be seen in a positive light. "We can't avoid boredom – it's an inevitable human emotion. We have to accept it as legitimate and find ways it can be harnessed. We all need downtime, away from the constant bombardment of stimulation. There's no need to be in a frenzy of activity at all times," she says.

Children who complain that they have nothing to do on rainy half-term breaks may find other things to focus on if left to their own devices. The artist Grayson Perry has reportedly spoken of how long periods of boredom in childhood may have enhanced his creativity. "We all need vacant time to mull things over," says Priyadharshini.

But if boredom can enhance our creativity and be a signal for change, why is it such a corrosive problem for some individuals?

People who have suffered extreme trauma are more likely to report boredom than those who have had a less eventful time. The theory is that they shut down emotionally and find it harder to work out what they need. They may be left with free-floating desire, without knowing what to pin it on. This lack of emotional awareness is known as alexithymia and can affect anyone.

Frustrated dreamers who haven't realised their goals can expend all their emotional energy on hating themselves or the world, and find they have no attention left for anything else. Bungee jumpers and thrill-seekers may also be particularly susceptible to boredom, as they feel the world isn't moving fast enough for them. They constantly need to top up their high levels of arousal and are always searching for stimulation from their environment.

"Boredom isn't a nice feeling, so we have an urge to eradicate it and cope with it in a counterproductive way," says Eastwood. This may be what drives people to destructive behaviours such as gambling, overeating, alcohol and drug abuse, he says, though research is needed to tease out whether there's a direct causal link.

"The problem is we've become passive recipients of stimulation," says Eastwood. "We say, 'I'm bored, so I'll put on the TV or go to a loud movie.' But boredom is like quicksand: the more we thrash around, the quicker we'll sink."