A report into the use of sedatives, tranquillisers and anti-depressants has shown a slight increase between 2007 and 2011.
Women and older adults are more likely to use the drugs, according to a survey carried out by the National Advisory Committee on Drugs.
However, their use is increasing among men and among 15-34 year olds.
The survey showed 16% of women will use sedatives and tranquillisers in their lifetime, compared with 12% of men.
While 13% of the women surveyed have used anti-depressants, only 8% of men did so. Last year, 6% of women surveyed took them, compared with 4% of men.
Overall more men said they used sedatives and tranquillisers and anti-depressants last year than in 2007.
Some 17% of adults aged between 34 and 64 used sedatives and tranquillisers in their lifetime and 13% used anti-depressants.
For people aged between 15 and 35 the usage rates are lower, at 10% and 7% respectively.
However, the increase in the use of sedatives and tranquillisers between 2007 and 2011 was bigger in the younger age bracket.