Abstract
While usually perceived as behaviour of the young, use of illicit drugs by people aged 50 and over is increasing in Europe and the USA. This increase largely reflects the ageing of general populations, and people who use drugs continuing to do so as they age. For those people dependent upon drugs [usually users of opiates (heroin) and stimulants (cocaine, crack cocaine and amphetamine)], the last 30 years has seen the advent of effective treatment and harm minimisation initiatives and, coupled with general advances in medicine, has increased the life expectancy of these drug users. Drug use by older people presents unique problems; biological systems and processes alter naturally across the life course and the effect of concurrent drug use on some of these systems is not well understood. The natural progression of certain diseases means that symptoms only manifest in older age and the lives of older drug users are likely to be characterised by considerable levels of morbidity. Further work is needed on the epidemiology of drug use by older people---a group of people who currently represent a hidden and vulnerable population.