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 population. These findings suggest that, even in memory-impaired populations, memory measures of malingering are valid.