International data suggests that between 20% and 30% of people seeking an ADHD diagnosis may be malingering, further complicating an already difficult diagnosis. An unhurried approach and specific tests can help distinguish genuine cases, facilitating access to the right care and averting potential harms from unnecessary treatment.
While some models associate malingering with antisocial intent, this likely only accounts for a small proportion of cases, says clinical psychologist Dr Grant Blake, clinical director of the Intensive Trauma Treatment Centre and Focused Potential in Queensland.
“Malingering is the intentional exaggeration or fabrication of symptoms or impairments for an external reward,” he explains. “By and large, malingering is just a behaviour that well-meaning, pro-social people do, but it’s to meet some sort of need or goal.”
Rewards may include access to medication, academic accommodations, compensation and avoidance of criminal prosecution.
The prevalence of suspected ADHD malingering in his private practice is about 20 to 25%, he says. “And that’s consistent with the international published literature on validity test failures. And we know that the prevalence rate may increase to about 40% in some studies when it’s a tertiary student.”
Partial malingering occurs when a patient has genuine symptoms but exaggerates their severity. A patient may truly struggle with concentration, for example, but overstate their impairment to help guarantee they’ll get an ADHD diagnosis, Dr Blake explains.
Full malingering is the complete fabrication of symptoms.
False imputation involves intentionally misattributing real symptoms caused by something else to ADHD, Dr Blake explains.
“So they know that they can’t focus because they’re distracted thinking about their boyfriend or girlfriend, or they’re a football player and know their focus hasn’t been the same since they had bumps to the head. But they want to blame everything on this potential diagnosis of ADHD for that reward of getting what they want.”
A genuine belief that difficulties are caused by ADHD is not malingering, he stresses.
“The distinction is conscious intent to deceive to obtain a benefit. That is why a thorough examination and differential diagnosis is important—many people might believe they have ADHD, but they are not trained to consider the many factors that can affect focus, restlessness, and impulse control.”
Australian clinical guidelines recommend conducting comprehensive assessments to diagnose ADHD, including a thorough clinical and psychosocial assessment. This should include a discussion about the patient’s symptoms and their impact on different aspects of their everyday life, they explain.
Dr Blake cautions against over-reliance on interviews and symptom questionnaires, noting patients can easily access online symptom lists, self-assessments and social media content describing ADHD traits.
Various factors can influence a patient’s responses, including confirmation bias, poor insight and a genuine misunderstanding of what’s causing their symptoms, he says.
“And we know that unstructured clinical opinions and interviews are not reliable detectors. If you think you’re a good lie detector, you’re wrong. There is a lot of published literature to that effect.”
Common self-report measures also have inherent limitations, he says, noting sensitivity and specificity statistics alone do not tell us how trustworthy a positive or negative result actually is. He recommends checking a test’s positive predictive value (PPV) and negative predictive value (NPV), which take the underlying prevalence of ADHD in the population being assessed into account.
More sophisticated tools, such as the Conners rating scales, may perform better, but even these are constrained by the interaction between test performance and ADHD’s prevalence.
Multiple self-assessments may not help, he adds.
“There’s a degree of redundancy to multiple methods of self-report, particularly when someone believes they have the condition or wants the condition.”
Information from school reports, teachers and caregivers is important—but may have some inherent, if unintentional, bias. For example, a teacher might feel frustrated and want extra support or, on the flip side, underreport because of concerns over potential social implications, Dr Blake says.
“We always have to weigh the quality of evidence available to us when arriving at a diagnosis.”
ADHD specialist Dr Alison Poulton, an academic paediatrician, senior lecturer at the University of Sydney and board advisor to ADHD Australia, notes the diagnostic criteria themselves have weaknesses.
“They are terrifically vague and imprecise, because they’re framed as ‘often’, meaning that the symptom has to occur significantly more frequently than it would in the general population—taking age and developmental level into account—and to a level that impacts functioning. Therefore, responses will vary depending on a person’s perception of what is normal,” she says.
“A second problem is that historically, they are derived from adults’ observations of children’s behaviour. And for diagnosing adults, they’re still framed in terms of third-party observations.”
“They don’t take any benefit from the much more sophisticated assessments of functioning that you can get if you ask an adult the right questions. The right questions aren’t necessarily the ones that have been enshrined in the DSM,” she says.
“I know someone who never loses his mobile phone because he wears it on a lanyard around his neck. If you ask if he loses his mobile phone, he’ll say no. And that’s the honest answer. But it’s because he’s using a strategy that most people wouldn’t have to use.”
“So you’ve got to delve into their function and what strategies they use to keep them on track.”
ADHD traits exist on a continuum, and diagnosis hinges on whether the symptoms cause significant functional impairment in everyday life—posing another potential conundrum, she adds.
To get by, people with ADHD sometimes cut back on the tasks they have to get through. While they may appear to be coping, ADHD is actually having a significant functional impact because it made them lower their goals, Dr Poulton explains.
“So they’re functioning at a lower level than they’re capable of functioning.”
Dr Poulton emphasises the importance of taking a detailed clinical history to understand the broader impact symptoms have on daily life, including secondary consequences of inefficiency such as fatigue, anxiety, depression and reduced self-esteem.
Dr Blake says teasing out the differences between poor insight, denial, partial malingering, full malingering, false imputation, and all the other clinical possibilities that could explain what’s going on is complex and nuanced—and validity tests can help.
For example, a 25-year-old who got themselves to the appointment, sat for an hour and shared their personal history may do worse on a validated performance validity test than a patient with severe dementia.
“That quickly highlights that there’s a major inconsistency here, that yes, they’re reporting symptoms that might sound believable. But give the person the opportunity to demonstrate it on an objective test and something funky emerges.”
While findings like this do not prove malingering, they do suggest the need for closer scrutiny, he says.
“Ultimately, validity tests assess whether symptom reports or test performance can be interpreted reliably. They do not independently diagnose ADHD or establish deliberate deception, and invalid results do not rule out genuine ADHD,” Dr Blake says.
The results need to be interpreted alongside the person’s history, everyday functioning and information from other sources.
Recent reviews in European Psychiatry and the Journal of Affective Disorders have emphasised the importance of validity testing in identifying malingering and improving diagnostic accuracy.
In general practice, the Rey 15-Item Memory and Recognition Test can be useful to explore if someone’s result was reliable.
If the overall picture still doesn’t add up, a psychologist experienced in ADHD and validity testing can help clarify what’s going on.
While patients are often desperate to get a diagnosis, Dr Blake recommends taking the time to gather sufficient evidence, weigh the quality of collateral information and seek further data when necessary.
“Our responsibility as healthcare providers is to not rush, but to do it faithfully, diligently,” he says.
“It’s better to get it right from the outset than to be backtracking on the potential iatrogenic harms for misdiagnosis or underdiagnosis years later.”
While it’s not always practical, assessments should ideally include input from multiple professionals, including GPs, psychologists and psychiatrists where appropriate.
“Yes, it might be initially slower, but does that save us time and money undoing the harms that we might have accidentally contributed to?”
Dr Blake recommends taking a non-confrontational approach, starting with succinct feedback that some assessment results cannot be confidently interpreted, so further clarification is needed.
Then explain that you can only develop a safe treatment plan based on what you know is reliable and shift the discussion to their concerns.
“You’re saying that you’re struggling at school. Let’s talk about that. You’re saying that you don’t like your workplace. Let’s focus on that.”
It’s important to understand and treat the patient’s difficulties, whatever their origin, he adds.
“Don’t deprive healthcare because of a common behaviour in the context of someone wanting something.”
Listen to expert interviews.
Click to open in a new tab
Browse the latest articles from Healthed.
Once you confirm you’ve read this article you can complete a Patient Case Review to earn 0.5 hours CPD in the Reviewing Performance (RP) category.
Select ‘Confirm & learn‘ when you have read this article in its entirety and you will be taken to begin your Patient Case Review.
