Opioid dependence is a major health concern across the world. The most recent prevalence estimates of opiate use in the Republic of Ireland indicate that there were 18,988 opioid users in Ireland in 2014, giving a rate of 6.18 per thousand population aged 15—64 years (95% CI: 6.09—6.98).1 Six per cent of this estimated population was under 24 years of age. Although recent trends suggest that the prevalence of problem opiate use in Ireland may have stabilised, it should be noted that estimates remain high, with other comparable studies suggesting that rates of use remain among the highest in Europe. Opioid substitution treatment (OST) is the main first-line treatment intervention for heroin dependence among adults. Nevertheless, while OST has been thoroughly evaluated in adult populations, few studies have examined its use in younger age groups, and there are concerns that OST is underutilised in adolescents with heroin dependence.

A recent Irish study investigated changes in drug use among adolescents receiving OST and also examined treatment attrition during the first 12 months of treatment.2 In this study, published in the BMC journal Pediatrics, data on all heroin-dependent patients (aged under 18.5 years) commencing OST were examined from one outpatient multidisciplinary addiction treatment service in Dublin. Drug use was monitored twice weekly using a urine drug screen (UDS). Change in the proportion of UDS negative for heroin was examined using the Wilcoxon signed-rank test. Attrition was explored via a Cox regression multivariate analysis.

Results

It was found that of 120 patients who commenced OST (51% female, mean age 17.3 years), 33% (n=39) persisted with OST until month 12. Of these patients, heroin abstinence was 21% at month 3 and 46% at month 12, although heroin use declined significantly from baseline to month 3 (p<0.001) and from month 3 to month 12 (p=0.01). Use of other drugs did not change significantly. Among factors associated with heroin abstinence, the study observed the following:

• None of the patients who had a previous psychiatric admission were abstinent (p=0.02).
• All of the patients who were using cocaine during month 12 were also using heroin (p=0.02).
• Abstinence was not significantly associated with a higher medication dose (p=0.88).
• Early reductions in heroin use, as evidenced by provision of at least one heroin negative sample during induction, tended to be associated with reduced likelihood of heroin abstinence at month 12 (p=0.07). 

Cox regression analyses indicated that patients who had no children, grew up in families with two parents, were in an intimate relationship with another heroin user, and who were abstinent from cocaine in pre-treatment drug screens demonstrated significantly lower rates of unplanned exit from treatment.

Conclusions

The authors concluded that the study confirmed that adolescents on OST can achieve substantial reductions in heroin use, with many doing so very early in treatment. In addition, after a year of treatment, almost one-half of adolescent heroin users were heroin-abstinent. The authors state that these findings should act as source of optimism for clinicians. Nevertheless, patient dropout from treatment remains a challenge and cocaine use before and during treatment may be a negative prognostic factor.

2  Smyth BP, Elmusharaf K and Cullen W (2018) Opioid substitution treatment and heroin dependent adolescents: reductions in heroin use and treatment retention over twelve months. BMC Pediatrics, 18: 151. https://www.drugsandalcohol.ie/29019/