One in 20 people suffers with frequent or chronic nightmares, writes Roger Dobson.
In one of the biggest studies in the area, results show that bad dreams are associated with health problems - from insomnia, fatigue and headaches, to depression and anxiety.
Mental health problems, such as depression, were five times more common in men and women who had regular nightmares.
'The high correlation between nightmare frequency and sleeprelated daytime consequences underlines the fact that nightmares might have a strong effect on the wellbeing of the patient, and should be treated,' says Dr Michael Schredl, of the Sleep Laboratory at the Central Institute of Mental Health in Mannheim, Germany.
Nightmares are defined as frightening dreams that awaken people from rapid eye movement or REM sleep, a time when there are high levels of brain activity.
In the new Chinese research, psychiatrists investigated nightmares in 9,000 adults, looking at the frequency, as well as who has them and any links with ill health.
The results showed that 5.1 per cent of people have frequent nightmares, defined as at least one a week. They were more common among women, with 6.2 per cent having one at least once a week compared to 3.8 per cent of men.
Those in the neurotic category were also more likely to have scary dreams, and researchers say there is evidence of a genetic susceptibility, too.
Frequency was also linked to income and unemployment. Those on the lowest incomes were 2.3 times more likely to have three or more nightmares a week compared to the more affluent.
Higher levels of stress associated with lower incomes and social status may predispose some people to nightmares.
In turn, greater frequency was also linked to an increased risk of insomnia and to a higher risk of daytime fatigue, headaches, and difficulty getting up in the morning.
Results also show that the risk of having a psychiatric disorder was 5.7 times greater for those with frequent nightmares compared with those without.
The top nightmares in the study
- Falling (39.5 per cent)
- Being chased (25.7)
- Being paralysed (25.3)
- Being late for an event (24)
- Close person disappears/ dies (20.9)
- Horror films (18.9)
- Unable to complete a task (17.3)