Derived trail making test cutoffs and malingering among substance abusers

The Trail Making test (TMT) is often used to screen for cognitive impairment in substance abusers. A possible limitation of the TMT in clinical settings is that substance abusers may malinger and give poor effort. Data from the Drug Abuse Treatment Outcome Study (DATOS) were analyzed to develop derived TMT cutoffs. Data were analyzed to determine number of substance abusers that fell beyond the upper end of the distribution of selected derived TMT scores at the 10, 5, and 1 percentiles. These percentiles were set for alcoholics (n = 1000), cocaine abusers (n = 4306), and heroin abusers (n = 1548) for TMT selected derived scores. Inspection of the selected TMT derived scores yielded an impression that the percentile values for the 3 sub-samples of primary drugs of abuse, alcohol, cocaine, and heroin, are actually very similar at each of the 3 percentile levels. This would suggest that these estimates are actually quite stable and reinforces the notion that they may be creditable estimates. The proper use of the derived TMT cutoff scores is to alert clinicians to the increasingly higher probability of poor effort when a substance abuser in one of the three groups scores beyond the one percent cutoff for the primary drug of abuse sample. Clearly, the use of these cutoffs needs further empirical validation before they would be considered as a single source to suggest malingering. Great caution is suggested in using these cutoff scores for clinical purposes with substance abusing patients in their current state of validation. In short, further research is warranted.