Performance validity tests measure whether effort on a particular task was adequate; they do not measure intent, and they do not classify the underlying disorder. A single marginal failure, particularly when a second indicator is passed, has limited specificity, and suboptimal effort can arise from pain, fatigue, medication, anxiety, low motivation or depression as well as from deliberate underperformance. Validity data must always be interpreted alongside the clinical history, the medical record and non-medical information rather than in isolation.
This distinction matters because the boundary between functional disorder, factitious disorder and malingering is one of intent, which cannot be measured directly. Several arguments weigh against feigning in the general functional population: patients typically accept unpleasant investigation and treatment, remain symptomatic when unobserved, do not usually gain financially, continue symptoms after claims are settled, and show reproducible physiologic abnormalities. Malingering is considered uncommon in clinical practice and is more often an issue in medicolegal settings; even there, a diagnosis requires converging evidence of deliberate deception for an identifiable external reward.
On the ABPN blueprint this maps to the Diagnostic procedures axis, because the competency tested is the correct interpretation and limits of a formal diagnostic test. Writing an unqualified conclusion of malingering on the strength of one failed indicator is both scientifically unsound and potentially damaging.
Incorrect Answers
- A. Malingering requires demonstrable deliberate deception for external gain, corroborated by multiple sources; a single marginal test failure cannot supply that.
- C. Validity testing does contribute useful information about effort, particularly in medicolegal contexts, and should be reported with appropriate caveats.
- D. Absence of financial gain argues against malingering but does not exclude factitious disorder, in which the reward is the sick role itself.
- E. Acceptance of unpleasant investigation is one of the arguments cited against feigning in functional disorders, not evidence for it.
Testing Pearls
- Performance validity tests assess effort on a task, not intent or diagnosis.
- Pain, fatigue, medication, anxiety and depression can all lower effort scores.
- Multiple converging sources are required before concluding that symptoms are feigned.
- Factitious disorder is motivated by the sick role; malingering by external reward.
- Malingering is uncommon in clinical practice and mainly an issue in medicolegal settings.
References
- Jankovic J, Mazziotta JC, Newman NJ, Pomeroy SL, editors. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022. p. 2086-2087.
- Bass C, Halligan P. Factitious disorders and malingering: challenges for clinical assessment and management. Lancet. 2014;383(9926):1422-1432.
- Stone J. Functional neurological disorders: the neurological assessment as treatment. Pract Neurol. 2016;16(1):7-17.
