The human immunodeficiency virus (HIV) targets and degrades the immune system and commonly exerts detrimental effects on the nervous system as well. In 2012, the Centers for Disease Control and Prevention estimated that more than 1.2 million people in the United States were living with HIV infection. Approximately half of HIV patients experience neurocognitive impairments in the domains of attention, executive functions, [Page 2005]psychomotor speed, episodic memory, or certain language or visuospatial functions. These impairments, broadly termed HIV-associated neurocognitive disorders (HAND), are classified in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), as either major or mild neurocognitive disorder due to HIV infection. Before describing these disorders in more detail and discussing prevalence, assessment, etiology, comorbid conditions, and outcomes, ...