Longitudinal studies of XXXX in a fifteen-year-old population. 1. Drug career.

@entity1 @entity734
A representative, stratified sample from a year cohort of ninth-graders, mostly 15 years of age, examined in 1968 with a questionnaire, was followed over a decade in official registers. After 5 and 8 years, subsamples were also interviewed. During the period in question there was a @entity734 pattern in the area of Gothenburg, the second city in Sweden with approx. 450,000 inhabitants. The sample comprised 1,047 individuals and the whole year cohort 5,367. The estimated proportions of registered drug abusers in the cohort were 9% @entity1 and 8% @entity1 . 3% @entity1 and 5% @entity1 had drug careers for 2 years or less, 1% @entity1 and 0.2% @entity1 for 10 years or more. Those who became registered had with few exceptions stated drug use in the school questionnaire or had attended special classes or dropped out of school prematurely. After 5 years 60-80% of the registered abuse remained among the @entity1 in these groups and 30-40% among the @entity1 . According to interviews abuse remained in 70-90% of @entity1 who had admitted drug use in the school survey and in 50-60% of the @entity1 from the same groups. According to both registers and interviews intravenous abuse of central stimulants had increased among @entity1 but decreased among @entity1 . After 11 years, 20-60% of the registered abuse remained in @entity1 and 5-60% in the @entity1 .
