"Although hard drug arrest rates were not associated with changes in the IDU rate, imprisonment might be. Arrest data may fail to capture incapacitation effects if arrests do not lead to incarceration or if sentences are brief.42 Furthermore, even data on time served may not reflect the perception of punitiveness among the population hypothesized to be deterred by incarceration.43 A study of incarceration and injection among 1603 IDUs, however, found that incarceration was negatively associated with injection cessation.7
"Because high arrest rates move many active IDUs from the community into the penal system, the lack of a negative relationship between arrest rates and IDU prevalence raises the question of why removal of IDUs does not reduce their number. One possible reason is that incarcerated IDUs are replaced by new IDUs. This might result if hard drug arrests or the fear of such arrests promote transitions to injecting among noninjectors.23,25–27 Another possibility is that, in MSAs [Metropolitan Statistical Areas] where hard drug arrests have been decreasing over time, the removal of new arrestees is balanced by the return of previously arrested IDUs from jail or prison. More research is needed on this question.
"Deterrence-based approaches to reducing drug use thus appear not to reduce IDU prevalence. They may harm public health: IDUs in MSAs with higher hard drug arrest rates have been found to have higher HIV prevalence.21 Furthermore, arrests for drug use disrupt the lives of drug users, their families, and their neighbors. High imprisonment rates for African American men have been suggested as a contributing factor to racial disparities in sexually transmitted infections in the United States.44,45 Alternative approaches such as harm reduction, which prevents HIV transmission and increases referrals to treatment, may be a better foundation for policy.46"
Samuel R. Friedman, PhD, et al., "Drug Arrests and Injection Drug Deterrence," American Journal of Public Health, February 2011, Vol. 101, No. 2, p. 348.