Forms of knowledge, cognitive impairment and drug abuse: a demonstration

Chronic abusers of alcohol and other drugs often exhibit persistent deficits on neuropsychological tests. These deficits are usually attributed to drug-induced brain dysfunction or to familial factors that depress performance independent of drug abuse. The aim of this study was to determine the plausibility of a third explanation: namely that some neuropsychological deficits of drug abusers arise because they acquire different forms of knowledge from non-drug abusers. This hypothesis predicts that drug abusers should excel on tests of knowledge that is related to their lifestyle. Sixty-three clients from a local methadone clinic and a comparison group of 24 non-abusing subjects who were knowledgeable about drugs listened to a song about cocaine addiction. They were asked to identify the title, artist, year the song was first popular and the meaning of the song. There were no significant differences between the groups in identifying the song title, artist or year, but the drug-abusers were significantly more likely to state that the song was about cocaine or drug addiction. In interpreting deficits by drug abusers on neuropsychological tests, differences in knowledge acquired should be considered.