Performance of substance abusers with memory deficits on measures of malingering

The effects of memory impairment on various malingering indices were assessed in a substance abusing population. Groups were formed by using scores from the Delayed Memory Index of the Wechsler Memory Scale-Revised and selecting individuals from an addictions recovery unit in the top and bottom quintiles. Quintile group differences were found for number correct on free and forced-choice recall on the 21-Item Wordlist; total time for grouped and ungrouped dots on the Rey Dot Counting procedure; and addition errors on the Memorization of 16 Items test. All differences found were in the direction of better performance by subjects with better Delayed Memory Index scores; however, all of the differences were small. With the exception of the free recall index from the 21-Item Wordlist, all subjects had scores on the malingering measures beyond the cutoffs typically used to detect malingering in clinical populations. These findings suggest that, even in memory-impaired populations, memory measures of malingering are valid.