Health Consequences of Illegal Drug Use

Chuan-Yu Chen; Keh-Ming Lin


Curr Opin Psychiatry. 2009;22(3):287-292. 

In This Article

Abstract and Introduction


Purpose of Review: The aim of this article is to review recent research on the health consequences of illegal drug use and possible risk factors, with a particular focus on prospective evidence.
Recent Findings: Mortality studies have revealed qualitative and quantitative changes in causes of death among heroin and injecting drug users (IDUs), probably due to increasing exposure to harm reduction programs, the introduction of highly active antiretroviral therapy (HAART), the aging of drug users, and rising concurrent use of illegal drugs and prescription drugs. For morbidity, nonfatal overdose is still one of the most important concerns; likewise the higher prevalence of hepatitis C among non-IDUs and hepatitis A, B, C coinfection. Cannabis use has been consistently reported to be associated with the emergence of psychotic symptoms, yet that seems not to be the case for anxiety and depressive disorders. Use of 3,4 methylenedioxymethamphetamine (MDMA) has been linked with short-term negative effects on cognitive performance (i.e. visual memory). A series of longitudinal studies have shown enduring unfavorable effects of prenatal cocaine and marijuana exposure on children's physical, cognitive, and language development.
Summary: Prospective evidence on illegal drug use in particular subpopulations may be needed to better understand health problems among users at different life stages and the possible long-term effects.


Over the past century, medicine and public health have made tremendous progress in reducing morbidity and lengthening life expectancy, but the pace of improvement seems not to be the same across all disease categories. Substance use and related problems have taken an increasingly heavy toll on health across different societies and populations, particularly in younger age populations and low-income and middle-income countries. In 2004, drug use disorders accounted for 0.2% of all deaths worldwide (approximately 91 millions deaths) and contributed to approximately 0.5% of disability adjusted life years (DALY).[1,2] A recent review on the burden of 11 mental disorders by Eaton et al.[3] reported that the category of drug abuse/dependence in general has a median relative risk of 2 for all-cause mortality and leads to an estimated annual cost of over 200 billion US dollars.

Prior clinical and epidemiological studies have shown that a broad array of adverse health consequences may be attributed to illegal drug use. The severity of adverse health effects varies, depending on individual characteristics (e.g. age, gender), pharmacological attributes (e.g. dose, purity, route of administration), context or situation (e.g. party scene or driving), and concurrent use of other drugs or alcoholic beverages.[4] In this review, we seek to identify and summarize some of articles recently published on health problems associated with illegal drug use (mainly in 2007 and 2008). The literature review was performed by searching MEDLINE (via Pubmed). Search-term categories included illegal drugs, illicit drugs, substance, and drug names (such as marijuana, cannabis, hash, weed, and hashish for marijuana). It was limited to the English language and human samples.

The present paper begins by reviewing the impact of illegal drug exposure on mortality and causes of death. With consideration of the strength of evidence, particular attention will first be paid to the literature concerned with prospective study design. Next, we briefly summarize some recent findings on health problems associated with illegal drug use, with a primary focus on cannabis, amphetamine-type stimulants (including ecstasy), cocaine, and heroin and other opiates; these are the most commonly consumed four categories of illegal drugs worldwide. Finally, we turn to the existing evidence of drug-associated negative health consequences in special populations and discuss some gaps that need to be addressed in future research.