The available data suggest that drug use has become more common among the adult general population aged 15-64 years in Ireland over recent years. Fewer than 2 in 10 adults reported use of any illicit drug during their lifetime in 2002-03, but this figure increased to approximately 3 in 10 in 2014-15. Similarly, last year and last month prevalence of use of any illicit drug has increased since the 2011 survey. The most recent survey, in 2014-15, suggests that cannabis remains the most commonly used illicit drug, followed by MDMA/ecstasy and cocaine. Illicit drug use is more common among males and younger age groups. Among young adults (aged 15-34 years), the prevalence of last year cannabis use was stable between the 2006-07 and 2010-11 surveys, but it was found to have increased in the most recent study. Reported last year use of MDMA decreased between 2006-07 and 2010-11 but increased substantially in 2014-15; cocaine use has remained stable.
In 2014-15, the reported prevalence of lifetime use of new psychoactive substance (NPS) among the adult general population aged 15-64 years was approximately 4 %. In contrast to trends observed for other illicit substances, data from the 2014-15 study demonstrate that the prevalence of NPS use among the Irish general population has decreased since the 2010-11 survey. Among young adults, last year prevalence decreased from 6.7 % in 2010-11 to 1.6 % in 2014-15.
Data on drug use among 15- to 16-year-old students are reported from the 2015 European School Survey Project on Alcohol and Other Drugs (ESPAD). This study has been conducted regularly in Ireland since 1999. For three of the eight key variables studied (lifetime use of cannabis, lifetime use of inhalants and lifetime use of NPS), Irish students reported prevalence rates that were slightly above the ESPAD average (based on data from 35 countries), although the differences were not substantial. Levels of non-prescribed use of tranquillisers or sedatives were below average, while levels of lifetime use of illicit drugs other than cannabis were similar to the overall average. The trend indicates a decrease in lifetime prevalence rates of cannabis between the 2003 and 2007 surveys, with a stabilisation in prevalence rates between 2011 and 2015.
Studies reporting estimates of high-risk drug use can help to identify the extent of the more entrenched drug use problems, while data on first-time entrants to specialised drug treatment centres, when considered alongside other indicators, can inform an understanding of the nature of and trends in high-risk drug use.
The estimate of high-risk opioid use in 2014 was based on a four-source capture-recapture method and indicated that there were 19 000 opioid users in Ireland (6.18 per 1 000 population aged 15-64 years), of whom almost two thirds lived in Dublin. In 2014, more than half of opioid users were aged 35 years or older, compared with less than one third in 2006, suggesting that this high-risk population is ageing.
Data from the specialised drug treatment centres indicate that opioids (mainly heroin) remain the most common primary drug among those entering treatment. Between 2006 and 2010, heroin was the main drug reported by first-time entrants, but this was superseded by cannabis in 2011, and this remained the case in 2017. The most notable trend is the continued increase in the number of cases presenting for treatment for problem cocaine use. Numbers of first-time entrants reporting cocaine as their primary drug have been increasing since 2012, reaching the highest level in 10 years in 2017. Both amphetamines and MDMA are rarely reported as the main problem drug by first-time entrants. Approximately one quarter of clients entering treatment are female; however, this proportion varies depending on primary drug and treatment programme.