| Popis: |
The distribution of an admission cohort (clients admitted during a given period of time) according to year of first use depends on the incidence for the various years and the waiting time (lag) to enter treatment. Peaks in the distribution of admissions can be due to incidence peaks or peaks in the waiting time distribution. Using groups of daily heroin users who share a common incidence distribution but who have different waiting times to enter treatment it is possible to separate the effects due to incidence from those due to waiting time. In this paper, voluntary heroin admissions, involuntary admissions, and admissions from individuals in prison are used to plot the distribution of the admission cohort (for 1975) by year of first use. Clients are further divided into two categories: those with no prior treatment experiences and those with one or more, for a total of six mutually exclusive and exhaustive groups. It is shown that all groups share a common peak, attributed to incidence, in 1969. The peaks of the waiting time distributions for those with no prior experiences are seen to be around two to three years. |
