Diagnostic overshadowing is when a health professional puts a new symptom down to a condition the person already has, such as a mental illness, learning disability, autism, physical disability, weight or gender identity, and so stops looking for another cause.1Mental Health Practice. Preventing diagnostic overshadowing to improve the physical health of people with severe mental illness A chest pain, a low oxygen reading or a change in behaviour gets treated as “just their anxiety” or “just their autism” rather than checked. It isn’t one careless doctor. It is a recognised thinking bias that can affect any clinician, and it falls hardest on groups that are already easy to dismiss.2PubMed. Cognitive bias and diagnostic overshadowing in trauma: The case of substance use disorder in patients with traumatic brain injury The real problem isn’t a wrong label but a search that ends too early, so what helps most is getting the other possibilities looked at.
Where the Term Comes From and What It Covers Now
The idea started with learning disability. Psychologist Steven Reiss first described it in 1982.3local.gov.uk. Diagnostic overshadowing and how it impacts on people with a learning disability and autistic people He noticed that mental health symptoms in people with learning disabilities were being dismissed as part of their disability.4local.gov.uk. Diagnostic overshadowing and how it impacts on people with a learning disability and autistic people As a result, real conditions such as depression went undiagnosed.5Diagnostic Overshadowing Dangers. Diagnostic Overshadowing Dangers
The meaning has since widened. About 25 years later the term came to mean physical symptoms wrongly blamed on a mental or emotional cause.6PubMed Central. Diagnostic overshadowing: An evolutionary concept analysis on the misattribution of physical symptoms to pre‐existing psychological illnesses Today it is most often used for physical symptoms put down to mental illness.7Journal of Public Health. Diagnostic overshadowing in mental health: a mixed-methods systematic review of its impact on health inequities and system-level responses It also covers symptoms put down to autism or learning disability without other causes being considered.8Local Government Association. Diagnostic overshadowing and how it impacts on people with a learning disability and autistic people
The common thread is that one known condition becomes the explanation for everything new. The symptom is real, but it gets filed under the old label. Because that label is real and does explain many things about the person, the shortcut feels sensible, which is why staff and families find it hard to notice in the moment.
This also separates it from an ordinary wrong diagnosis. A misdiagnosis usually follows an investigation that pointed the wrong way. With overshadowing the investigation never really happened, because an answer seemed already available. Both can delay treatment.
Who Is Most Likely to Be Affected
Overshadowing often affects people with severe mental illness, such as schizophrenia or major depression.9[OpenAI/Course Material]. What Is Diagnostic Overshadowing in Healthcare? Emergency department staff report it as a real problem for people with mental illness who arrive with physical symptoms.10PubMed Central. Diagnostic Overshadowing and Other Challenges Involved in the Diagnostic Process of Patients with Mental Illness Who Present in Emergency Departments with Physical Symptoms – A Qualitative Study It also reaches people with a substance use problem. After a ruptured spleen from injury, they were somewhat more likely to have diagnosis and surgery delayed, even when they were not intoxicated.11PubMed. Diagnostic Overshadowing: Delayed Management in Substance Use Disorder Patients With Splenic Injury
Autistic people and people with a learning disability can have a new illness blamed on their diagnosis.12Local Government Association. Diagnostic overshadowing and how it impacts on people with a learning disability and autistic people In people with learning disabilities, self-injury can be a sign of tooth or head pain rather than behaviour.13PubMed. Diagnostic overshadowing: self-injurious behaviour as a manifestation of pain in the head and neck In older people with dementia, communication problems and poor sight or hearing add to the risk.14Nursing Older People. Exploring the complexities of symptom recognition and management in older people with dementia and multimorbidity People with mobility disabilities report cancer signs being blamed on their disability or on emotions.15PubMed Central. Perspectives of Patients with Pre-existing Mobility Disability on the Process of Diagnosing Their Cancer
People who can’t easily describe symptoms are at extra risk. Someone with a learning disability, advanced dementia or limited speech may show pain through agitation, withdrawal, refusing food or hurting themselves, rather than saying where it hurts. Family members and paid carers who know what is usual for the person are often the first to notice a change.
People in larger bodies describe symptoms being put down to weight, which delays care and erodes trust.16IGI Global. The Biased Scale: How Medical Fatphobia Undermines Health Equity and Patient Trust People with raised pressure around the brain describe being told “just lose weight.”17PubMed Central. “Just lose weight”: weight-based medical bias and experiential expertise in intracranial hypertension Trans people describe “trans broken arm syndrome,” where any problem is blamed on their gender identity or transition.18PubMed. Trans broken arm syndrome: A mixed-methods exploration of gender-related medical misattribution and invasive questioning Trans people with a chronic illness or disability meet this barrier more often because they see doctors so often.19PubMed. Recognizing and Addressing Health Care Barriers for Transgender and Nonbinary People Living With a Chronic Illness or Disability Belonging to more than one group stacks the risk, since each label offers staff another ready explanation for a new symptom.
What It Looks Like in Real Life
In one UK legal case, a woman admitted during poor mental health had repeatedly low oxygen levels.20Barcan and Kirby Solicitors in Bristol. What is diagnostic overshadowing? Staff treated these as part of her mental health episode.21Barcan and Kirby Solicitors in Bristol. What is diagnostic overshadowing? A blood vessel problem in her lungs was missed, and she later had a series of strokes.22Barcan and Kirby Solicitors in Bristol. What is diagnostic overshadowing?
People with severe mental illness describe a similar pattern with cancer: symptoms put down to their mental illness, which delayed diagnosis.23PubMed. Exploring the perceived impact of stigma on the cancer experience of people with severe mental illness They also describe being told less and left out of decisions.24PubMed. Exploring the perceived impact of stigma on the cancer experience of people with severe mental illness
Certain phrases can signal overshadowing. Hearing “it’s probably just your anxiety” before any examination or test suggests the explanation came before the checking. A new behaviour in an autistic person described as “just part of their autism,” without asking what changed recently, is another example. Being told to “lose weight and come back” without being examined suggests the symptom was blamed on body size alone. And being asked about gender identity or medication when you came in with an unrelated injury suggests attention has moved away from the problem you brought. A single phrase is not proof, and what matters is whether a sensible check followed it.
Some signs should never be explained away. Abnormal readings such as oxygen level, heart rate or temperature are objective. So is a symptom that is new or different from the person’s usual pattern. Symptoms that persist or worsen despite mental health treatment need another look, and weight loss, bleeding or lumps need checking whatever the history.
Why Clinicians Fall Into It
Overshadowing is a thinking shortcut where a known condition crowds out other diagnoses.25PubMed. Cognitive bias and diagnostic overshadowing in trauma: The case of substance use disorder in patients with traumatic brain injury Several forces combine to feed it: system pressures, limited mental health training, stigmatising attitudes and difficulty communicating needs.26PubMed. Seeing the complete picture: A systematic review of mental health consumer and health professional experiences of diagnostic overshadowing
In a busy clinic the shortcut feels reasonable. An existing diagnosis offers a quick, ready explanation, and in a short appointment the first plausible answer is rewarded because it saves time. Anxiety really can cause chest pain and palpitations, so the explanation is often partly true, which makes the error easy to make and hard to spot. The step that gets skipped is asking what else this could be, and that question separates a careful assessment from a rushed one.
None of this is the patient’s fault. The responsibility for checking other causes lies with the clinician, not with the patient having to argue the case well enough.
Why It Matters for Health and Life Expectancy
People with mental illness have higher rates of heart disease and cancer and die from them more often.27Erkenntnis. Diagnostic Overshadowing in Psychiatric-Somatic Comorbidity: A Case for Structural Testimonial Injustice Poorer physical healthcare, including overshadowing, is one reason.28Erkenntnis. Diagnostic Overshadowing in Psychiatric-Somatic Comorbidity: A Case for Structural Testimonial Injustice People with serious mental illness often die 10 to 20 years earlier, mostly from physical illness.29[OpenAI/Course Material]. What Is Diagnostic Overshadowing in Healthcare? Delays allow complications that worsen outcomes.30Mental Health Practice. Preventing diagnostic overshadowing to improve the physical health of people with severe mental illness Trust suffers too: people who feel dismissed may put off the next visit, and the illness may be more advanced when they return.
The effect continues even after death. For over half of adults with cerebral palsy, the disability is wrongly recorded as the cause of death.31PubMed Central. Postmortem Diagnostic Overshadowing: Reporting Cerebral Palsy on Death Certificates Real causes get hidden and become harder to prevent.32PubMed Central. Postmortem Diagnostic Overshadowing: Reporting Cerebral Palsy on Death Certificates
How to Speak Up for Yourself or Someone You Care For
Start by saying clearly what is new and how it differs from usual. Ask directly what physical causes have been ruled out. If the person has trouble describing how they feel, bring a carer who knows their normal. Good communication and pain-assessment tools also help people who can’t easily describe pain.33PubMed. Diagnostic overshadowing: self-injurious behaviour as a manifestation of pain in the head and neck
Preparing helps. Write down when the symptom started, what has changed since, and any readings you have, such as temperature or blood pressure. Note what makes it better or worse, since this helps the clinician think about physical causes. Bring a list of current medicines, because side effects and interactions can themselves cause new symptoms. Start with the physical symptom before going into mental health history, so it is heard first as its own problem.
A few questions can keep the check on track. Ask “Could this be something physical, and how would we find out?” to prompt a check before an explanation. Ask “What tests would you do for someone without my diagnosis?” so the same standard of care is applied. Ask “What should make me come back urgently?” so you leave with a clear safety net. And ask for a note in your record that you raised the symptom, so it is documented if it continues.
If you are still dismissed, ask for a second opinion or another clinician. Patient advice and complaints services can help, and urgent care is the right place to go if symptoms worsen. Serious harm from a missed diagnosis can amount to legal negligence.
What Health Services Are Doing to Prevent It
Training helps. Brief feedback reduced overshadowing among trainee psychologists.34Training and Education in Professional Psychology. A brief feedback intervention for diagnostic overshadowing Simulations built from real incidents and patient experiences teach staff to spot bias, and let them practise in a safe setting before it affects a real patient.35PubMed. ‘You don’t see what I see’: Co-designing simulation to uncover and address cognitive bias in healthcare
Warning signs are being studied too. In emergency departments, age over 70, abnormal heart rate and abnormal temperature flagged hidden physical illness in psychiatric patients.36PubMed. Diagnostic Overshadowing of the Psychiatric Population in the Emergency Department: Physiological Factors Identified for an Early Warning System Because the score missed some patients, a normal result does not clear someone. A simple score from these caught about 7 in 10 such patients, so it supports judgement rather than replacing it.37PubMed. Diagnostic Overshadowing of the Psychiatric Population in the Emergency Department: Physiological Factors Identified for an Early Warning System
In written test cases, AI tools showed this bias less than mental health professionals, though not zero.38JMIR Mental Health. Comparing Generative Artificial Intelligence and Mental Health Professionals for Clinical Decision-Making With Trauma-Exposed Populations: Vignette-Based Experimental Study The cases were written, not real patients, so the finding points to a possible aid for checking decisions, not proof that such tools work in clinics. Fixes are needed at the system level as well as for individuals.39SpringerLink / Erkenntnis. Diagnostic Overshadowing in Psychiatric-Somatic Comorbidity: A Case for Structural Testimonial Injustice