Drug use disorders among people convicted of large-, moderate- and small-scale drug supply crimes: A register-based...

Heavy drug use has been associated with small-scale drug crime, but the substance use histories of individuals involved in the manufacturing, smuggling and wholesaling of larger quantities of drugs [here referred to as serious drug crimes (SDC)] have been largely unexamined. We estimated and compared the prevalence of drug use disorders (DUDs) among individuals with and without convictions for SDC, and we compared the characteristics of individuals convicted of SDC with and without a history of DUD.

A register-based retrospective comparative study.

Denmark.

Individuals convicted of SDC (large-scale: n = 232, 98.3% male; moderate-scale: n = 2955, 92.5% male) and two comparison groups without histories of SDC (general population: n = 3187, 92.9% male; small-scale drug supply: n = 7630, 94.0% male), all born in 1985 or later and residents of Denmark.

Drug crime scale was determined from Danish legal categories and sentence lengths, which primarily reflect drug quantity. Large- and moderate-scale SDC groups were convicted under Penal Code Section 191, with the former receiving a prison sentence of ≥ 5 years for a Section 191 offense. The small-scale drug supply comparison group was convicted under the Euphoriants Act but not Penal Code Section 191. The general population comparison group was age- and sex-matched to the SDC groups and had no Penal Code Section 191 conviction. DUD prior to first supply-related drug crime, socio-demographic characteristics, criminal history, alcohol-related disorders and psychiatric problems were identified using national registers. Adjusted prevalence of DUD was estimated as predicted probabilities from logistic regression models including age and sex as covariates.

Adjusted DUD prevalence among both SDC groups was higher than in the general population group but lower than in the small-scale supply group [large-scale: 18.5%, 95% confidence interval (CI) = 13.8%-23.3%; moderate-scale: 24.3%, 95% CI = 22.8%-25.8%; small-scale: 29.4%, 95% CI = 29.2%-29.6%; general population: 3.2%, 95% CI = 2.6%-3.8%]. Individuals convicted of SDC with a history of DUD were more likely than those without a history of DUD to have prior alcohol [odds ratio (OR) = 1.92, 95% CI = 1.49-2.46], psychiatric (OR = 4.70, 95% CI = 3.87-5.71) and employment problems (OR = 1.65, 95% CI = 1.35-2.01).

Individuals convicted of serious drug crimes in Denmark appear to have a lower prevalence of drug use disorders than individuals convicted of small-scale drug supply but a higher prevalence than members of the general population.