Prevalence Estimates of Symptom Feigning and Malingering in Spain

The prevalence of feigning and concealment of Covid-19 infections in an international sample

We asked 463 participants from 21 countries whether they had feigned and/or concealed having a coronavirus infection during the pandemic period. 384 respondents (83%) reported having experienced a coronavirus infection. They were, on average, younger and reported more chronic health issues than participants who said they had never been infected. 65 (14%) admitted to having feigned the infection. Prevalence doubled (28%) when asked if they knew anyone who had feigned a coronavirus infection. Main motives for feigning were to stay at home and to obtain sick leave. As to having concealed a coronavirus infection, 56 (12%) responded affirmatively, but when asked about others, the prevalence reached 51% (n = 210). The most common reasons for concealment were to avoid letting others know and to not miss an event. Thus, both feigning and concealing infections can occur on a nontrivial scale, directly affecting prevalence rates in studies that rely on self-reported data collected from social platforms.

Classification accuracy and resistance to coaching of the Spanish version of the Inventory of Problems-29 and the Inventory of Problems-Memory: A simulation study with mTBI patients

Objective: The present study aims to evaluate the classification accuracy and resistance to coaching of the Inventory of Problems-29 (IOP-29) and the IOP-Memory (IOP-M) with a Spanish sample of patients diagnosed with mild traumatic brain injury (mTBI) and healthy participants instructed to feign. Method: Using a simulation design, 37 outpatients with mTBI (clinical control group) and 213 non-clinical instructed feigners under several coaching conditions completed the Spanish versions of the IOP-29, IOP-M, Structured Inventory of Malingered Symptomatology, and Rivermead Post Concussion Symptoms Questionnaire. Results: The IOP-29 discriminated well between clinical patients and instructed feigners, with an excellent classification accuracy for the recommended cutoff score (FDS ≥ .50; sensitivity = 87.10% for coached group and 89.09% for uncoached; specificity = 95.12%). The IOP-M also showed an excellent classification accuracy (cutoff ≤ 29; sensitivity = 87.27% for coached group and 93.55% for uncoached; specificity = 97.56%). Both instruments proved to be resistant to symptom information coaching and performance warnings. Conclusions: The results confirm that both of the IOP measures offer a similarly valid but different perspective compared to SIMS when assessing the credibility of symptoms of mTBI. The encouraging findings indicate that both tests are a valuable addition to the symptom validity practices of forensic professionals. Additional research in multiple contexts and with diverse conditions is warranted.