Estimating the Prevalence of Illegal Drug Use

A generic globally applicable integral equation allows the estimation of hidden drug use. Formulas for estimating the prevalence of drug use are provided for both the assumed and known latency period. Estimates of prevalence of opiate use in Ireland ranging from 7,955 [5,789, 10,122] to 11,986 [8,792, 15,181] with prevalence rates ranging from 2.7 [2.0, 3.5] per 1,000 to 4.1 [3.0, 5.2] were obtained. The model can be implemented by service providers and planners if numbers of first treatments for drug use and the latency period are known or assumed.