Until now, illicit drug use has not been common in older people.
However, it is likely to become more common as generations that use drugs more frequently reach an older age.
New UK research published in the journal Age and Ageing has found that the lifetime use of cannabis, amphetamine, cocaine and LSD in 50-64 year olds has significantly increased since 1993 and is much higher than lifetime use in adults aged over 65.
Cannabis was the most frequent drug used. Lifetime cannabis use was reported by 1.7% of people aged 65 and over, and by 11.4% of people aged 50-64 in the sample.
In the inner city sample, these proportions were 9.4% and 42.8% respectively. Recent cannabis use (i.e.within the last 12 months) was reported by 0.4% of people aged 65 and over, and by 1.8% of people aged 50-64.
In the inner city sample, these proportions were 1.1% and 9.0% respectively.
While the series of national UK surveys carried out from 1993 to 2007 did not contain data on the oldest end of the age range, patterns of cannabis use in middle age were consistent with a rapid increase in 50-64 year olds, lifetime use had increased approximately ten-fold from 1.0% in 1993 to 11.4% in 2007, and recent use had multiplied by a similar extent from 0.2% in 1993 to 2.0% in 2007.
Lifetime amphetamine use had increased substantially although recent reported use remained uncommon.
Tranquiliser use showed more stability.
Senior author of the study Prof. Robert Stewart, from King's College London, comments that "the key message of this paper confirms something which has been long-suspected but which has not, to our knowledge, ever been formally investigated in the UK - namely that illicit drug use will become a more common feature in older generations over the next one to two decades.
One particular issue is that we really know very little about the effects of drugs like cannabis in older people but will need to work fast if research is to keep up with its wider use at these ages.
"Our data suggest, at the very least, that large numbers of people are entering older age groups with lifestyles about which we know little in terms of their effects on health and would benefit from further monitoring - in particular, health service staff providing care for older people should be aware of the possibility of illicit drug use as part of the clinical context, particularly as previous research and policy reports have suggested that this is often missed.
Little is known about the prevalence of illicit drug use in late-life. The prevalence of some illicit drug use in people aged 50-64 years is higher than that in 65+ year olds (recent and lifetime use of cannabis 1.8% and 11.4% respectively, 9.0% and 42.8% respectively).
Projected increasing use of cannabis in older age groups is confirmed by past trends observed in previous mental health surveys in 1993 and 2000.
The clinical and public health relevance of these potential secular changes in both lifetime and recent prevalence is not clear but should be a research priority.
There is a need to develop a treatment infrastructure that is sensitive to problems of older illicit drug users.
Fahmy V, Hatch SL, Hotopf M, Stewart, R.
Prevalence of illicit drug use in people aged 50 years and over from two surveys.