People who feign poor performance on a psychological test, for example to support a claim for compensation, do not necessarily behave dishonestly on all aspects of assessment. That's according to Anthony Ruocco and colleagues who say that, while previous research has examined malingering within various psychological domains, such as within psychopathology or neuropsychology, few studies have investigated whether people who feign performance in one domain tend to also do so across the board.
One hundred and five compensation-seeking outpatients who had been referred to a private clinic for neuropsychological evaluation, were tested by the researchers for neuropsychological malingering and psychiatric malingering.
The measures they used included the 'Test of Memory Malingering' (TOMM), which requires participants to view 50 pictures and then afterwards say which picture in a series of pairs was among those originally viewed. Performance on the test is known to be relatively unaffected by a broad range of neuropsychological impairments which is what makes it a useful measure of malingering.
Psychiatric malingering was assessed using the 'Millon clinical multi-axial inventory-III' (MCMI-III) – a 175 item self-report test. It contains scales measuring personality disorders, mood disorders, and four measures of response style. The latter aspects of the test reveal how much the participant is responding in a socially desirable way, how open they are, and how overly self-deprecating.
From the results, the researchers estimated that between 2 and 10 per cent of the sample (depending on the cut-offs used) were exaggerating their symptoms on the personality/ psychopathology test, and that between 30 and 34 per cent were feigning poor performance on the neuropsychology tests.
Crucially, they found that the participants who feigned cognitive impairment tended to answer honestly on the psychopathology questions, and vice versa, with those exaggerating psychiatric symptoms tending to perform honestly on the memory tests.
Given their findings, the researchers advised: "Neuropsychologists must thus not make the error of assuming that an exaggerated personality profile invalidates neuropsychological data. The present investigation provides strong evidence for a dissociation between these two forms of symptom exaggeration in the context of a neuropsychological evaluation."
The researchers added that this dissociation between psychiatric and neuropsychological malingering made intuitive sense in the current context of a neuropsychological compensation claim. People undergoing an assessment in such a context may "not necessarily view psychiatric disturbance as related to their reportedly impaired cognitive status, " the researchers said.
However, there was a suggestion in the data of a subgroup of individuals who scored particularly poorly on the memory tests and who also reported exaggerated psychiatric symptoms. The researchers said further research with larger sample sizes is needed to investigate this possibility.
Ruocco, A.C., Swirsky-Sacchetti, T., Chute, D.L., Mandel, S., Platek, S.M. & Zillmer, E.A. (In Press). Distinguishing between neuropsychological malingering and exaggerated psychiatric symptoms in a neuropsychological setting. The Clinical Neuropsychologist.
Tombaugh, T.N. (2007). The test of memory malingering (TOMM): Normative data from cognitively intact, cognitively impaired, and elderly patients with dementia. Archives of Clinical Neuropsychology, 19, 455-464.
Millon, T. Davis, R. & Millon, C. (1997). Manual for the Millon Clinical Multiaxial Inventory-III (MCMI-III) (2nd edn). Minneapolis, MN: National Computer Systems.