Modelling the role of amelioration and drug lords on drug epidemics and the impact of substance abuse on the dynamics of HIV/AIDS

[摘要] ENGLISH ABSTRACT: Substance abuse is an imminent danger on the health of both substance users and nonusers.In general, abuse of psychoactive substances is associated with high risk behaviour,mortality and morbidity. The drug use cycle involves inextricably intertwined variantssuch as production, trading and usage of both licit and illicit addictive substances. Thedynamics of substance use involve initiation, addiction, rehabilitation/treatment and quitting/recovery. In response to supply and abuse of monster drugs, control strategies suchas law enforcement and rehabilitation have been stepped up to reduce access to drugs bytargeting drug kingpins and harm reduction respectively. In this thesis, we model the factorsaffecting the prevalence of substance abuse, the effect of drug lords on the prevalenceof substance abuse, and the impact of substance abuse on the prevalence of HIV/AIDS.We formulate mathematical models based on systems of autonomous differential equationsdescribing the dynamics of the sub- populations involved in the drug using cycle.We examine the effects of amelioration, rehabilitation/treatment and re- initiation on theprevalence of substance abuse. Our results suggest that, recruitment into rehabilitationand amelioration in the presence of quitting for light users reduce the prevalence of substanceabuse; re-initiation and amelioration without quitting for light users increase theprevalence of substance abuse. Our assessment of the impact of drug lords and the effectof law enforcement on drug epidemics shows that, the presence of drug lords seriouslyconstraints the efforts to reduce substance abuse since they increase access to drugs. However,law enforcement if stepped up in response to the population of drug lords, greatlyreduces the prevalence of substance abuse. Given the associated influence of drugs on highrisky behaviour, as a cofactor for sexually transmitted infections, we assess the influence ofsubstance abuse on the prevalence of Human Immunodeficiency Virus (HIV). Our resultsshow that dissemination of information regarding HIV and drug use reduces HIV prevalencewhereas, there is faster spread of the epidemic and high prevalence with increasedsexual contact.

[发布机构] Stellenbosch University