Examining the use of the M-FAST with criminal defendants incompetent to stand trial.

The Miller Forensic Assessment of Symptoms Test (M-FAST) was developed to provide evaluators with a brief, reliable, and valid screen for malingered mental illness. This study examined the initial validity of the M-FAST in a sample of 50 criminal defendants found incompetent to stand trial because of a mental illness. The M-FAST total score and items were compared with the Structured Interview of Reported Symptoms (SIRS) and the fake-bad indicators of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2). Results indicated good evidence of construct and criterion validity, demonstrated by t tests, receiver operating characteristics analysis, and high correlations between the M-FAST, SIRS, and the fake-bad indices on the MMPI-2. Tentative cut scores for the M-FAST total score and scales were examined and demonstrated high utility with the sample of criminal defendants incompetent to stand trial.