Effect of substance abuse on visuographic function.

The effect of substance abuse on visuographic functions was investigated by comparing 4 groups from an Arabian Gulf population: 63 heroin abusers, 14 alcohol abusers, 43 polydrug abusers, and 48 control subjects. The visuographic function was evaluated using Benton's Revised Visual Retention Test. Analysis of covariance yielded an over-all group effect on both number correct and errors. Assessment of significance of differences between groups showed that the polydrug-abusing group and the heroin-abusing group scored significantly lower than the nonabusing group on number correct. All 3 substance-abusing groups scored significantly higher than the non-abusing group on errors, which seems a better predictor of cognitive impairment. Classification of subjects on the basis of their scores on the Benton test showed that a significant proportion of subjects in each substance-abusing group were classified as impaired. It is concluded that the present findings were consistent with prior reports for European and American subjects.