Data extracted from the Hospital In-Patient Enquiry (HIPE) scheme were analysed to determine trends in non-fatal overdoses discharged from Irish hospitals in 2010. There were 4,562 overdose cases in that year, of which 40 died in hospital.  The 4,522 discharged cases are included in this analysis. The number of overdose cases increased by 8% between 2009 and 2010, following a decrease of 13% between 2008 and 2009 (Figure 1).  


                    

Characteristics of cases
Gender
In the years 2005–2010 there were more overdose cases among females than among males (Figure 2), with females accounting for 53% of all overdose cases in 2010.

Age group
One quarter of all overdoses between 2005 and 2010 occurred in those aged 15–24 years, with the incidence of overdose decreasing with age (Figure 3). However, the number of under-25s was lower in both 2009 and 2010 than in previous years.  In 2005, 40% of cases were aged under 25 years, compared to 34% in 2010.

Area of residence
In 2010 there were 1,003 (22%) overdose cases among people resident in Dublin (city and county), 3,492 (77%) cases among people resident outside Dublin, and 77 cases recorded as having no fixed abode or being resident outside of Ireland.

Drugs involved
Table 1 presents the positive findings per category of drugs and other substances involved in all cases of overdose in 2010. Non-opioid analgesics were present in 34% (1,552) of cases. Paracetamol is included in this drug category and was present in 27% (1,129) of cases. Psychotropic agents were taken in 22% (1,000) and benzodiazepines in 24% (1,086) of cases. There was evidence of alcohol consumption in 12% (561) of cases. Cases involving alcohol are included in this analysis only when the alcohol was used in conjunction with another substance.

Table 1   Category of drugs involved in overdose cases, 2010 (N=4,522)

Overdoses involving narcotics or hallucinogens
Narcotic or hallucinogenic drugs were involved in 13% (588) of overdose cases in 2010. Figure 4 shows the number of positive findings of drugs in this category among the 588 cases. The sum of positive findings is greater than the total number of cases because some cases involved more than one drug from this category.  Opiates were used in 80% of the cases, cocaine in 16% and cannabis in 8%.

 
Overdoses classified by intent
In 67% of cases the overdose was classified as intentional (Figure 5).

Table 2 presents the positive findings per category of drugs and other substances involved in cases of intentional overdose in 2010. Non-opioid analgesics were involved in 42% (1,258) of cases, benzodiazepines in 28% (832) and psychotropic agents in 27% (820).

Table 2   Category of drugs involved in intentional overdose cases, 2010 (N=3,005)