Hidden need for drug treatment services: Measuring levels of problematic drug use in the North West of England

Background: In the North West of England, data on drug users are routinely collected from a variety of agencies including specialist treatment centres, police and probation services. However, the covert nature of drug use means that alone, these conventional monitoring systems cannot provide the epidemiology required to target and develop drug treatment and prevention initiatives. Methods: Utilizing surveillance data and capture-recapture techniques we estimate the rates of problematic drug users by age and sex in five North West health authorities and one local authority. Results: Analyses show concentrations of problematic drug use in large metropolitan areas (Liverpool and Manchester) with levels as high as 34.5 and 36.5 per 1000 population (ages 15-44), respectively, and, for males, levels exceed 50 per 1000 in three authorities. Patterns of prevalence for those aged 25 and over differed from those in the younger age groups, with disproportionate levels of young users outside metropolitan areas. The proportion of young users already in treatment (21.3 per cent) was lower (older users, 35.3 per cent), with overall proportions in treatment varying between health authorities (range 26.2-46.5 per cent). Conclusion: With a multi-agency approach, established monitoring systems can be used to measure hidden populations of drug users. Estimates of the current populations of such users in the North West of England suggest that planned increases of people in treatment by 100 per cent would fail to accommodate even current level of problematic users. A holistic approach to new initiatives must ensure that the high lever of relapse once drug users are discharged are reduced and that the needs of young users are addressed before prolonged treatment is required.