Heroin addicts show impairment of information processing at the iconic level.

Heroin addicts (n = 100) and healthy controls (n = 100) were examined for their information processing ability at iconic (100 ms, 125 ms) as well as relatively deeper (250 ms, 500 ms) levels. Subjects were asked to identify briefly exposed photographs of familiar objects through an electronic tachistoscope. Addicts showed significant impairment of visual information processing at iconic but not at deeper levels.