EFFORT, EXAGGERATION, AND THE LIMITS OF THE MALINGERING LABEL

One of the most common questions I get from attorneys on both sides is some version of, “Is this person malingering?” It’s a fair question. In a medicolegal evaluation, the credibility of the data matters just as much as the data itself. If the results are not valid, everything built on top of them, from the diagnosis to the impairment rating, becomes invalid. But the answer to that question is rarely as simple as yes or no, and the word “malingering” carries more weight than most people realize.

Every neuropsychiatric evaluation I conduct includes measures designed to assess the validity of the results. These fall into two broad categories, and it is helpful to understand the difference between them.

Performance validity tests (PVTs), also known as effort measures, look at whether a person put forth adequate effort on cognitive testing. Some are standalone tests, created specifically for this purpose. Others are embedded within standard cognitive measures, such as Reliable Digit Span, so that effort can be monitored throughout the evaluation rather than at a single point in time. These tasks are designed to be easy enough that even individuals with significant brain injuries, i.e. dementia, perform well on. When someone performs below expected levels, it tells us their effort is suspect. Some PVTs use a forced choice format, where a person could get roughly half the items correct simply by guessing. When someone scores significantly below chance on these tasks, it is a stronger indicator, because it suggests the person knew the correct answer and intentionally selected the wrong one.

Symptom validity tests (SVTs) look at how a person reports their symptoms. On instruments like the MMPI-2-RF and MBMD, validity scales help identify whether someone is reporting symptoms in an unusual, inconsistent, or exaggerated way. Some scales flag reporting of rare psychiatric symptoms, others flag overreporting of somatic complaints, and others identify inconsistent or random responding. These scales also work in the other direction. Some individuals minimize their problems or present themselves in an overly favorable light, which can be just as important to identify.

It is important to note that these measures tell us about the credibility of the data. They do not tell us about a person’s character, and they do not tell us why the person responded the way they did. That distinction is often lost, and it is where many reports run into trouble.

As a golden rule of thumb, I never interpret any piece of data in isolation. One below expected score on a single validity measure is not, by itself, a basis for a conclusion. Even individuals who are trying their best can fail an isolated measure, particularly when they are in significant pain, are heavily medicated, or are severely depressed. This is why the research supports using multiple validity measures throughout an evaluation, and why the pattern across those measures matters far more than any single score.

Beyond the validity measures themselves, I look at the full picture. I consider consistency between test scores and the person’s reported daily functioning. I review medical, employment, and treatment records, including how symptoms have been described over time and to different providers. I look at whether complaints have stayed stable, improved, or escalated, and whether that course makes sense given the nature of the injury. I consider behavioral observations during the interview and testing, such as how the person navigates the office, follows conversation, recalls their own history, and manages the length of the evaluation. I also look at whether the pattern of results makes sense neurologically. Certain injuries produce certain patterns base on what we know about neuroanatomy and neurochemistry and results that do not fit any known pattern deserve a closer look.

For example, if someone with a mild concussion performs worse than individuals with severe dementia, yet drove themselves to the appointment, gave a detailed and organized history, and recalled specific dates without difficulty, that inconsistency is meaningful. On the other hand, if validity concerns are limited to one measure and everything else lines up with the records and my observations, that tells a very different story. Convergence across multiple sources of information is what makes an opinion defensible, and it is what allows that opinion to hold up under scrutiny.

The DSM defines malingering as the intentional production of false symptoms, motivated by external incentives such as financial compensation, avoiding work, or obtaining medication. Notice the two key elements: intent and motive. Neither one can be directly measured by a test. Malingering is also not a mental disorder. It is a description of behavior, and labeling someone as malingering is essentially a statement about why they did what they did.

When an injured worker shows signs of overreporting or inadequate effort, there can be many reasons behind it. Some individuals are genuinely distressed and are, in effect, crying for help. They may have felt dismissed by providers, their employer, or the system as a whole, and they worry they won’t be believed unless they emphasize how bad things are. Others are dealing with emotional dysregulation, depression, anxiety, or chronic pain that colors how they experience and describe their symptoms. Some have developed a genuine belief that they are more impaired than they are, which is a clinical issue in its own right.

And yes, some are in fact motivated by external gain and feigning altogether. However, in a medical population, these factors often overlap, and the same person may be influenced by more than one at the same time. Therefore, it is speculative for any evaluator to claim certainty about which one is driving the presentation.

For this reason, I am careful with the term. Language such as “noncredible performance,” “invalid profile,” or “symptom overreporting” describes what the data show without assigning an intent that cannot be proven. This is not about softening the findings. It is about staying within what the evidence can actually support, which is what a forensic opinion should always do.

In my view, the more useful question is not why someone is exaggerating, but what we do about it. When validity concerns are present, I state them clearly in the report and explain what they mean for the rest of the findings. I adjust my interpretation accordingly. Scores obtained under questionable effort likely underestimate true ability, so I do not treat them as an accurate measure of impairment. I rely more heavily on the data that are valid, on the records, and on my observations. When the cognitive data are too unreliable to interpret, I say so, rather than assigning a rating that the data cannot support. In most cases, when someone fails an effort measure, I will actually not proceed with cognitive testing.

Invalid results do not mean there is no injury, and a valid injury does not mean exaggeration should be overlooked. A person can have a real condition and still overstate it. A person can also fail an effort measure for reasons that have nothing to do with external gain. Our job is to separate what is credible from what is not, as objectively as possible, and to explain how we got there.

Validity testing is one of the most important tools in forensic neuropsychology, but it is only one tool. A sound opinion comes from integrating test data, records, and observations, and from being transparent about the limits of what any evaluator can know. It is also what gives the trier of fact something reliable to work with, and that is what serves everyone involved.

SAME SYMPTOMS, DIFFERENT CAUSE: THE HIGH COST OF GETTING COGNITIVE COMPLAINTS WRONG

Complaints of poor memory, difficulty concentrating, slowed thinking, and mental fatigue are common following an industrial injury. When there is a reported head injury, these symptoms may quickly be attributed to a concussion or traumatic brain injury. However, cognitive complaints are not unique to neurological injury.

Pain, disrupted sleep, depression, anxiety, medication effects, and other medical conditions can produce remarkably similar symptoms. In many cases, several of these factors are occurring at the same time. Determining what is actually driving the cognitive complaints is therefore an important part of a comprehensive neuropsychological evaluation.

This distinction matters not only diagnostically, but also because it can significantly affect treatment, prognosis, and the expected permanence of the cognitive difficulties.

For example, an individual experiencing poor concentration and forgetfulness due primarily to chronic pain and fragmented sleep may require a very different treatment approach than someone with cognitive deficits resulting from a neurological injury. Similarly, cognitive complaints associated with depression or anxiety may improve substantially when the underlying psychiatric condition is appropriately treated.

The appropriate provider may also differ. Depending on the underlying cause, treatment may be most appropriately directed by a neurologist, psychiatrist, psychologist, sleep specialist, pain management physician, or another medical provider. In some cases, cognitive rehabilitation may be appropriate. In others, treating sleep, pain, or mood may be the more effective intervention.

The expected duration of treatment can also vary considerably. Treatment directed toward an acute neurological condition may follow one course, while treatment for chronic pain, longstanding psychiatric symptoms, or a primary sleep disorder may require an entirely different timeline. Without an adequate differential diagnosis, treatment can continue for prolonged periods without addressing the primary factors maintaining the symptoms.

Just as importantly, the expected permanence of cognitive difficulties can vary depending on their underlying cause. Cognitive symptoms related to treatable factors such as sleep disturbance, depression, anxiety, pain, or medication effects may improve as those conditions improve. In other cases, objective cognitive deficits associated with a neurological condition may persist despite appropriate treatment. Therefore, determining the likely source of the cognitive complaints is important before conclusions are reached regarding prognosis, permanent impairment, or the need for long-term treatment.

The timing and course of symptoms are also important. Understanding an individual's pre-injury functioning, when symptoms first appeared, and how they have changed over time can help distinguish longstanding difficulties from those associated with an industrial injury. A history of depression, sleep disturbance, pain, or cognitive complaints does not exclude an industrial contribution, but it provides an important baseline for determining what actually changed following the injury.

This has obvious implications for medical utilization and cost. Repeated neurological consultations, imaging, cognitive rehabilitation, or extensive neuropsychological testing may add considerable expense if the primary contributors to the reported cognitive difficulties are actually untreated depression, chronic pain, poor sleep, medication effects, or some combination of these factors. Conversely, attributing legitimate neurological impairment solely to psychiatric or pain-related factors could result in necessary treatment being overlooked.

The goal, therefore, should not be to minimize cognitive complaints simply because alternative explanations exist. Rather, the goal is to determine, within reasonable medical probability, which factors best account for the individual's presentation and the relative contribution of each.

A careful differential diagnosis considers the mechanism of injury, objective findings, symptom course, medical and psychiatric history, medications, sleep, pain, emotional functioning, performance validity, and neuropsychological test results. No single symptom or test result should be interpreted in isolation.

In the medical-legal setting, getting the diagnosis right has consequences beyond the diagnostic label. It helps identify the appropriate treatment, the appropriate provider, the reasonable duration of care, the expected prognosis and permanence of the cognitive difficulties, and ultimately whether the treatment being recommended is actually addressing the condition responsible for the individual's symptoms.

SHAKEN, NOT STRUCK: UNDERSTANDING INERTIAL BRAIN INJURY

Most people picture a brain injury as the result of a direct blow — head meets object, object meets head. But some of the most consequential neurological injuries involve no impact at all. These are called inertial brain injuries, and understanding the physics behind them helps explain why a person can walk away from a car accident, a fall, or a sports collision looking perfectly fine, only to struggle with memory, attention, mood, etc. weeks later.

The brain is a soft, gel-like organ suspended in cerebrospinal fluid inside a rigid skull. When the head experiences rapid acceleration or deceleration — as in a whiplash-type car crash, a fall, or a violent shake — the skull and brain do not move in perfect unison. The skull stops or changes direction faster than the brain tissue inside it. This mismatch creates rotational and shear forces, not just linear ones. Rotational acceleration is particularly damaging because brain tissue tolerates straight-line, or translational, forces reasonably well but is far more vulnerable to twisting forces. The brain's various structures — gray matter, white matter, blood vessels — have different densities and different rates of deceleration, so they lag behind one another during the injury event. That differential movement is the mechanical heart of an inertial injury, and it can happen with no external impact to the head.

At the microscopic level, this differential movement stretches and twists axons, the long, thread-like projections that neurons use to communicate with one another. It helps to think of the brain's white matter as something like a thick bundle of wires running through the walls of a house. Each wire, or axon, has to stay intact along its entire length to carry a signal properly. Bend or jostle the bundle gently and the wires flex and recover. But twist the whole bundle sharply and unevenly, the way rotational forces do inside the skull, and individual wires inside it can stretch past their limit, fray, or lose their internal integrity, even though the outer casing of the bundle looks completely undamaged from the outside. That is essentially what happens with axonal shearing: the axon's internal transport system, its own version of the wire's conductive core, gets disrupted, even when the brain as a whole looks intact on the surface. When axons are stretched beyond their elastic capacity, the injury is called diffuse axonal injury. In more severe cases, the axon can swell, disconnect, and undergo a slower secondary degeneration over hours to days, meaning the full extent of injury isn't always apparent immediately. Because axons run throughout the brain, much like wiring runs throughout every room of a house, diffuse axonal injury tends to be widespread rather than localized, which is why symptoms can be broad, affecting attention, processing speed, memory retrieval, and executive functioning simultaneously rather than producing a single, clean deficit. The areas most frequently affected include the junctions between gray and white matter, the corpus callosum, and the brainstem — regions where tissue of different density meet and shear stress concentrates, similar to where a wire bundle bends sharply around a corner and takes on the most strain.

The mechanical damage to axons also sets off a cascade of chemical changes inside the brain, sometimes called the neurometabolic cascade of injury. Stretched and disrupted cell membranes cause ions to flow abnormally across them, triggering an uncontrolled release of the neurotransmitter glutamate. Glutamate is normally essential for healthy brain signaling, but in excess it overactivates neighboring neurons, a process called excitotoxicity, which places further stress on cells already weakened by the mechanical injury. This ionic disruption forces brain cells to work harder to restore their normal balance, sharply increasing their demand for glucose and energy at precisely the time when blood flow to the injured area is often reduced. The result is a temporary mismatch between how much energy the brain needs and how much it can actually deliver, which can last for days to weeks after the initial injury. This chemical and metabolic disturbance, layered on top of the structural axonal damage, is thought to contribute to the fatigue, difficulty concentrating, and sensitivity to cognitive or physical exertion that many patients describe well after the injury itself has technically "healed."

This is where inertial injury becomes clinically tricky. Conventional CT and standard MRI are often normal in cases of diffuse axonal injury, particularly in mild-to-moderate cases, because the damage occurs at a microscopic, axonal level rather than as a visible mass or bleed. More sensitive sequences can help. Susceptibility-weighted imaging and gradient echo MRI are more sensitive to the microhemorrhages that sometimes accompany axonal shearing, while diffusion tensor imaging, largely a research and specialized clinical tool, can detect disruptions in white matter tract integrity that standard MRI misses. Even so, a normal scan does not rule out a real injury. This gap between imaging and lived symptoms is one of the most important, and most misunderstood, aspects of inertial brain injury, and it's a frequent point of dispute in both clinical and legal settings.

Because structural imaging can under-detect diffuse axonal injury, neuropsychiatric testing plays a central role in characterizing its functional impact. Standardized cognitive testing can identify patterns consistent with diffuse, multi-domain involvement, including slowed processing speed, reduced sustained attention and working memory, difficulty with verbal or visual memory retrieval and encoding, and executive dysfunction affecting planning, cognitive flexibility, and inhibition. A thorough evaluation also incorporates performance validity testing to ensure that results reflect genuine effort and are interpretable, along with a review of pre-injury baseline functioning, mood, sleep, and other factors that can influence cognitive performance. No single test result proves an inertial brain injury in isolation; the value comes from the overall pattern, considered alongside the mechanism of injury, imaging, and clinical history.

Inertial brain injury sits at an interesting intersection of physics, cellular biology, and behavior. The mechanism, differential movement of brain tissue relative to the skull, is well established in the biomechanics literature. What remains genuinely difficult is translating that mechanism into individual diagnosis and prognosis, given the limitations of current imaging and the wide variability in how people recover. 

Good clinical practice acknowledges both: the injury is real and mechanistically well understood, and the tools we have to measure it in any one person are still imperfect. That combination is exactly why a multifactorial approach is crucial; imaging where appropriate, careful history-taking, and formal neuropsychiatric testing remain the most reliable way to understand what has actually happened inside a person's head.