What are the features of malingering?

Features of Malingering

Malingering is characterized by intentional fabrication or gross exaggeration of symptoms motivated by external incentives, with key diagnostic features including poor effort on testing, inconsistent physiological findings, erratic breathing patterns, and disproportionate symptom reporting relative to objective findings. 1, 2

Core Defining Characteristics

• Intentional production of false or exaggerated symptoms driven by external incentives such as avoiding work/duty, obtaining financial compensation, evading criminal responsibility, or procuring drugs 3, 4, 5
• Not a mental disorder but rather a deliberate act that can coexist with genuine psychiatric conditions including antisocial personality disorder, factitious disorders, or other mental illnesses 4, 5
• Diagnosis of exclusion requiring systematic evaluation to rule out legitimate medical and psychiatric conditions 3

Cardiopulmonary Exercise Testing (CPET) Features

When malingering presents as exercise intolerance, specific physiological patterns emerge:

• Low VO₂ peak with high heart rate reserve and breathing reserve, indicating premature test termination despite physiological capacity to continue 1
• Failure to reach lactate threshold or normal rather than low lactate threshold values 1
• Atypically irregular breathing patterns with erratic fluctuations in end-tidal and arterial PCO₂, including frequent sighing and panting with changing functional residual capacity 1, 2
• Patient symptom scores totally disproportionate to observed distress levels, often exceeding what is seen even in patients with severe chronic disease 1, 2

Neurological Examination Findings

Physical examination reveals characteristic inconsistencies:

• Positive Hoover's sign: When testing the "weak" leg, involuntary downward pressure occurs from the supposedly weak leg when the patient pushes down with the "normal" leg against resistance 2, 6
• Give-way weakness: Sudden inconsistent responses during resistance testing with variable strength when tested repeatedly or in different contexts 2, 6
• Drift without pronation: In true hemiparesis, a drifting arm pronates, whereas nonorganic weakness shows drift without this expected pronation 2, 6
• Non-anatomical patterns: Weakness distribution that doesn't follow known neurological pathways or dermatomes 2, 6

Features During Apparent Unconsciousness

When malingering presents as pseudosyncope or feigned unconsciousness:

• Closed eyes during unconsciousness are highly suspicious, as truly unconscious patients typically have open or partially open eyes 2
• Normal pulse and blood pressure during apparent loss of consciousness strongly suggest pseudosyncope 2
• Lack of pallor and diaphoresis during the episode, which would be expected in true syncope 2
• Prolonged apparent loss of consciousness with frequent episodes, whereas true syncope typically lasts seconds to less than 1-2 minutes 2
• Little physical harm despite frequent episodes, as true syncope often results in injury from unprotected falls 2
• Preserved reflexes and resistance to passive movements that would not occur in true coma 2

Behavioral and Contextual Clues

• Marked discrepancies between reported stressors and objective findings, with symptoms that seem exaggerated relative to the clinical picture 4
• Knowledge of secondary gain is critical: Understanding what the patient stands to gain from the diagnosis (disability benefits, avoiding legal consequences, obtaining medications) helps contextualize findings 2
• Inconsistent performance across different examiners or settings, with variable presentation depending on who is observing 6

Diagnostic Confirmation Strategies

• Normal EEG during apparent unconsciousness confirms pseudosyncope 2
• Transcranial Doppler showing maintained cerebral perfusion during apparent loss of consciousness rules out true syncope 2
• Tilt-table testing with simultaneous transcranial Doppler and EEG monitoring provides definitive differentiation when clinical suspicion is high 2
• Symptom validity tests and psychometric testing can detect inconsistent effort patterns 7
• Actigraphy with concurrent light sensors can verify reliability when diary information may be unreliable 2

Common Clinical Pitfalls

The primary challenge is that malingering by definition requires intentionality, which clinical skills alone cannot definitively establish 7. Malingering exists on a spectrum and is not an all-or-nothing presentation 7. Clinicians must avoid premature labeling while systematically documenting objective inconsistencies. The NEAL strategy (neutral, empathetic, and avoid labeling) is recommended when caring for patients suspected of malingering 3.