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AUSTIN, Texas -- Malingering should be considered when diagnosing post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI) in certain situations such as forensic settings, according to a review of current data.

Since PTSD and TBI have similar symptoms and are both most commonly diagnosed in veterans, it may be increasingly difficult to distinguish between the two, particularly since anywhere from 6% to 44% of those with TBI also have PTSD, reported Jeffrey Guina, MD, a forensic psychiatrist in Michigan.

The DSM-5 as "intentional production of false or grossly exaggerated physical or psychological symptoms, motivated by external incentives such as avoiding military duty, avoiding work, obtaining financial compensation, evading criminal prosecution, or obtaining drugs."

TBI and PTSD may be differentially incentivized in private and veteran's affairs (VA) disability systems, which may lead to false reports, Guina and colleagues explained in a poster at the American Academy of Psychiatry and the Law (AAPL) meeting.

While PTSD generally results from past trauma, and TBI often follows a physical brain injury such as direct force, a blast injury, or diffuse axonal shearing, both can have similar fMRI findings, particularly within the dorsolateral prefrontal, orbitofrontal, medial frontal, and anterior cingulate cortices, Guina reported.

PTSD patients will often present with more emotional symptoms, including trauma-related intrusions or avoidance of experience that may resemble past trauma, while TBI patients often present with more specific neurological symptoms such as headache, dizziness, photophobia, or tinnitus. However, both groups of patients may present with things like poor concentration, mood changes, trouble sleeping, or peritraumatic amnesia, he said.

Over time, PTSD may have delayed expression and worsen, while TBI symptoms tend to gradually improve for up to 1 year. Both may lead to an increased risk of developing dementia and lead to dysfunction and difficulties at work. Overall, TBI commonly involves cognitive and emotional symptoms similar to PTSD, but often without physical symptoms or clear indications of neurological abnormalities on tests like fMRIs, he said.

The first objective of a provider should be to take a detailed history of the patient's response to trauma and brain injury in order to see if TBI or PTSD may be at play, Guina said. In terms of treatment, trauma-focused psychotherapy and serotonergic agents tend to be more effective in patients with PTSD, while cognitive rehabilitation therapy and vocational rehabilitation are more suitable for TBI patients.

However, these treatment plans tend to be developed based on patient-reported symptoms, which may be indistinguishably similar between the two groups of patients, Guina said.

The gold standard in identifying patients with PTSD is the Clinician Administered PTSD Scale (), which works great in the clinical setting, said Guina. In the forensic setting, although it can be helpful to perform a Test of Memory Malingering (TOMM) or Minnesota Multiphasic Personality Inventory (MMPI) in patients that present with PTSD or TBI symptoms, it may still be difficult to definitively say someone indeed either has PTSD or TBI, or does not.

Patients who have malingering TBI or PTSD may be deliberately falsifying their symptoms in order to achieve some sort of external gain, such as disability payments or dismissal from a lawsuit. However, when approaching these cases, forensic psychiatrists may sometimes have limited options in corroborating the symptoms that patients report.

Differences in the way VA and private disability systems function may be contributing to patients reporting false claims of either illness. For example, in the VA disability system, moderate forms of PTSD are automatically qualified to receive 50% disability, whereas a moderate form of TBI may get 30% to 40% of disability.

"From a forensic perspective, there's this really interesting difference between the VA disability system and the private disability system where they differentially incentivize these conditions," Guina said. "Once you hit 50%, you get total care in the VA system for all your conditions, whereas 40% and below is only for the conditions you got disability for."

From a private disability standpoint, patients may be inclined to present with symptoms with TBI when malingering, as they would get more services for neurological conditions, for which payments are not time limited. Private policies may often have the right to "cut off" patients with PTSD after 2 years.

"It makes it really important to try to get this right even though it's very difficult, or near impossible sometimes," Guina said.

Guina said one way to avoid false reports is to perform neuropsychological testing. While both PTSD and TBI may demonstrate some overlap in increased symptoms like response inhibition, verbal memory, or attention regulation, results from neuropsychological testing of a patient with PTSD are typically less severe and often predate trauma, Guina reported.

Neuroimaging, however, is not ready to be used as a primary means of diagnosis and may, in some cases, be used irresponsibly, such as presenting overly scientific data to a jury, which may not be able to sufficiently interpret their validity.

"This is not standard of care to do fMRIs, and I don't think that's ready for prime time for diagnosis," Guina stated. "It's just in the nascent, early stages of the literature that they're finding these changes that look very similar, which might explain why there's symptom overlap."

Editors' note: This article has been updated to indicate that Guina recommended neuropsychological testing to rule out false reports of PTSD or TBI (not neuroimaging).

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