“…Based upon a substantial literature demonstrating that substances of abuse, such as cocaine and opiates, can both impair the function of CD4 ϩ lymphocytes and macrophages (Klein et al, 1993, Mao et al, 1996, Baldwin et al, 1997, Eisenstein and Hilburger, 1998Friedman et al, 2003) and potentiate the expression of HIV-1 in these cells (Peterson et al, 1990(Peterson et al, , 1992Bagasra and Pomerantz, 1993;Nair et al, 2000, Li et al, 2002Roth et al, 2002;Steele et al, 2003), it has been postulated that abuse of these drugs may serve as a cofactor in the progression of HIV-1 infection. The role of substances of abuse in development of HIV-1-associated dementia (HAD), one of the most devastating complications of AIDS, is supported by a growing body of epidemiological and histopathological evidence (Wang et al, 1995;Davies et al, 1997;Bell et al, 1998;Bouwan et al, 1998;Goodkin et al, 1998;Tomlinson et al, 1999), as well as by studies of molecular mechanisms whereby drugs of abuse and HIV-1 interact in causing neuronal death (Nath et al, 2002).…”