Did brain trauma lead to crime?
Mr. P pleads not guilty to rape charges, claiming a head injury 8 years ago caused personality changes, psychosis, and violent behavior. Is he malingering?
In the forensic setting, the preferred personality test is the MMPI-2.15 It consists of 567 items, with 10 clinical scales and several validity scales. The F scale, “faking good” or “faking bad,” detects people who are answering questions with the goal of appearing better or worse than they actually are. The Personal Assessment Inventory (PAI)16 is a 344-item test with a 4-point response format. The 22 scales cover a range of important axis I and II psychopathology.
SIRS17 is the gold standard in detecting malingered psychiatric illness; it includes questions about rare symptoms and uncommon symptom pairing. M-FAST18 was developed to provide a brief, reliable screen for malingered mental illness. It has shown good validity and high correlation with the SIRS and MMPI-2.
Tests of exaggerated cognitive impairment are extremely important in evaluating patients who claim to suffer from complications following TBI. TOMM19 —a 50-item recognition test designed to discriminate between true memory-impaired patients and malingerers—is the most studied and valid of such tests. Defendants’ scores that meet the recommended criteria for detecting malingering—≥5 errors on the retention trial—were found to also report a history of head injury.1
Although not as well validated, the Portland Digit Recognition Test (PDRT)20 is an alternative to the TOMM. This test is a forced-choice measure of recognition designed for assessing the possibility of malingering in individuals claiming mental illness because of head injury. The Victoria Symptoms Validity Test (VSVT)21 is used in outpatient and inpatient settings and also uses a forced-choice model to assess possible exaggeration or feigning of cognitive impairments. Finally, the Word Memory Test (WMT)22 is a neuropsychological assessment that evaluates the effort participants put forth.
Table 5
Standardized diagnostic instruments for detecting malingering
| Test | Clinical use |
|---|---|
| Personality | |
| MMPI-2 | F scale detects lying. Several validity scales |
| PAI | Covers a range of axis I and II psychopathology |
| Psychotic symptoms | |
| SIRS | Gold standard in detecting exaggerated psychotic symptoms |
| M-FAST | Screening tool to assess exaggerated psychosis; brief and reliable |
| Cognitive impairment | |
| TOMM | Highest validity of all tools to test memory malingering |
| PDRT | Assesses the possibility of malingering. Not widely studied and validity/reliability are suspect |
| VSVT | Useful for inpatient and outpatient settings |
| WMT | Evaluates effort put forth by the participant |
| M-FAST: Miller Forensic Assessment of Symptoms Test; MMPI-2: Minnesota Multiphasic Personality Inventory; PAI: Personal Assessment Inventory; PDRT: Portland Digit Recognition Test; SIRS: Structured Interview of Reported Symptoms; TOMM: Test of Memory Malingering; VSVT: Victoria Symptoms Validity Test; WMT: Word Memory Test | |
OUTCOME: Unsupported claims
Mr. P’s hospital records reveal a very minor head trauma that resulted in no structural brain abnormalities on imaging tests. Collateral interviews with Mr. P’s family and close friends fail to support the defendant’s claim that after the accident he began to experience behavioral changes and periods of psychosis. Mr. P’s SIRS and TOMM scores indicate malingering, and the psychiatrist did not support his NGRI defense.
Related resource
- Williamson DJ. Neurocognitive impairment: feigned, exaggerated, or real? Current Psychiatry. 2007;6(8):19-37.
Disclosure
Dr. Nasrallah receives research grant/research support from Forest Pharmaceuticals, GlaxoSmithKline, Janssen, Otsuka America Pharmaceuticals, Pfizer Inc., Roche, sanofi-aventis, and Shire, is on the advisory board of Abbott Laboratories, AstraZeneca, Janssen, Novartis, Pfizer Inc., and Merck, and is on the speakers’ bureau for Abbott Laboratories, AstraZeneca, Janssen, Novartis, Pfizer Inc., and Merck.
Dr. Farrell reports no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.
