Drug abuse and addiction have been inextricably linked with HIV/AIDS since the beginning of the epidemic. While intravenous drug use is well known in this regard, less recognized is the role that drug abuse plays more generally in the spread of HIV— the virus that causes AIDS—by increasing the likelihood of highrisk sex with infected partners.¹ This is because of the addictive and intoxicating effects of many drugs, which can alter judgment and inhibition and lead people to engage in impulsive and unsafe behaviors.

Drug abuse and addiction can also worsen the progression of HIV and its consequences, especially in the brain. In animal studies, methamphetamine increased HIV viral replication;² in human methamphetamine abusers, HIV caused greater neuronal injury and cognitive impairment compared with nondrug users.³,⁴