A drug misuser prevalence study in a rural English district

A capture-recapture method was used to estimate the total prevalence of drug (opiates, amphetamines or cocaine) misusers in a rural English district. Unique identifying information on known misusers was obtained from four agencies, including general practitioners, in contact with them. Log-linear modelling produced a complex model, suggesting that the 518 known misusers represented 47% of the estimated true number, giving an estimated prevalence of 2.5 per 1,000 population (CL: 1.6–9.4). This method may not provide precise estimates of misuser population sizes and should be used in conjunction with other methods for estimating need.