Sleeping pills prescribed to millions of people every year do not work in the long term, a study has found.
Scientists found no difference in sleep quality or duration between those who took the medication for one to two years.
The findings applied to a range of types of pharmaceuticals, from benzodiazepines, and Z-drugs to other hypnotics.
The research team said that rather than taking such medication long term, patients should receive cognitive behavioural therapy to help them sleep.
Meanwhile, the UKs premier insomnia body, the Sleep Charity, said on Tuesday night that the study showed that drugs failed to tackle the root problem.
In the Western world, insomnia is thought to affect between 10 and 30 per cent of adults at any one time, according to the Economic and Social Research Council.
The group has also calculated that one in 10 British adults regularly take some kind of sleeping tablet, with an accompanying risk of addiction.
For the new study, published in BMJ Open, a team at Brigham and Womens Hospital in Boston compared 238 women who had started using medication to tackle insomnia with 447 matched women who were not on sleeping drugs. The average age was 49.5.
Sleep disturbances were defined as difficulty falling asleep, frequent awakening and waking up early, all ranked on a five-point scale.
On average, both groups of women reported difficulties on one in three nights, waking frequently two in three nights, and waking up early one in three nights.
Overall, more than 70 per cent of women reported disturbed sleep at least three times a week, regardless of whether they were on sleep medication or not.
Around half of the women were current or former smokers and one in five were moderate to heavy drinkers, both of which may affect sleep quality.
