The relationship between performance validity test failure, fatigue, and psychological functioning in Long COVID

<b>Objective:</b> At times, patients with Long COVID fail performance validity tests (PVTs) for cognitive measures and symptom validity tests (SVTs) embedded in formal personality measures. This is the first study, to our knowledge, to examine whether self-reported symptoms on the Personality Assessment Inventory (PAI) and the Modified Fatigue Impact Scale (MFIS) were related to performance validity in Long COVID patients. <b>Method:</b> Participants were 175 individuals diagnosed with Long COVID who completed four PVTs, the MFIS, and the PAI. There was evidence for nots based on medical records review for 25.71% of the patients. Based on PVT performances, patients were assigned to one of three groups: Pass group (no PVT failures), Intermediate group (1 PVT failure), or Fail group (2+ PVT failures). <b>Results:</b> 84.57% of participants were in the Pass group, 9.14% in the Intermediate group, and 6.29% in the Fail group. There was a not a significant difference in external incentive frequency between groups. Only one significant group difference on the PAI scales and subscales was found, with slightly greater somatization symptoms (SOM-S) reported in the Fail group relative to the Pass group (<i>η²</i> = .03). The MFIS was not significantly different between groups. <b>Conclusions:</b> These findings suggest that PVT failure is not associated with fatigue or PAI responses, except on the somatization subscale.