Diagnostic overshadowing is a systemic error in healthcare where a patient’s new physical symptoms are mistakenly attributed to a pre-existing diagnosis, often a mental health disorder or intellectual disability. This occurs when a clinician focuses so heavily on the known condition that they fail to thoroughly investigate other possible causes for the patient’s current complaints. The incorrect assumption is that the presenting issue is simply a manifestation of the established diagnosis, rather than a separate medical problem. This bias prevents a comprehensive medical workup, meaning treatable physical illnesses may be overlooked. Diagnostic overshadowing is a significant contributor to health inequities and poorer health outcomes for specific patient groups.
Vulnerable Populations Where Overshadowing is Common
Individuals with intellectual disabilities (ID) face a higher risk of diagnostic overshadowing because symptoms of pain or illness are often expressed through changes in behavior. A new onset of challenging behavior may be wrongly labeled as a psychological issue inherent to the ID, rather than a signal of underlying physical distress. Communication difficulties compound this issue, as patients who rely on non-verbal cues may struggle to articulate their discomfort.
People diagnosed with severe mental illnesses (SMI), including schizophrenia or bipolar disorder, are also highly susceptible. Clinicians may interpret physical complaints, such as chest pain, as a symptom of anxiety or a psychosomatic manifestation of their psychiatric condition. This is problematic because individuals with SMI already have a greater incidence of physical health conditions, such as cardiovascular disease and diabetes.
The risk extends to those on the Autism Spectrum Disorder (ASD), whose unique sensory profiles can be misinterpreted. Clinicians may attribute discomfort or physical distress to the patient’s neurological profile, dismissing the need for a full medical investigation. These populations often experience historical bias, leading to an expectation that their symptoms are unreliable.
Cognitive Biases and Systemic Roots of the Problem
The root causes of diagnostic overshadowing lie in the intersection of cognitive shortcuts and systemic pressures within healthcare. A primary factor is anchoring bias, where a provider relies too heavily on the patient’s existing chronic or psychiatric diagnosis. Once this anchor is set, subsequent information, like new physical symptoms, is interpreted through that lens, making it difficult to consider alternative diagnoses.
This process is compounded by premature closure, which occurs when a clinician stops the diagnostic investigation once they believe they have an answer. Concluding that a patient’s complaints are psychosomatic or behavioral based on their chart history closes the door on further necessary testing. The stigma associated with mental illness acts as a form of implicit bias, predisposing some providers to view these patients’ complaints as less credible.
Systemic constraints further enable this problem. Time pressures from short appointment slots limit the opportunity for clinicians to conduct the detailed history taking and comprehensive physical examination required. Many healthcare professionals also have limited training in managing complex co-morbidities, especially the interaction between physical and mental health issues.
The Impact of Delayed or Missed Diagnosis
The consequences of diagnostic overshadowing are severe, leading to increased morbidity and mortality rates among affected populations. When acute physical illnesses are misattributed to a known diagnosis, the delay in treatment can be life-threatening. Symptoms of conditions like appendicitis, sepsis, or a stroke have been mistakenly labeled as a psychiatric episode or behavioral disturbance.
This diagnostic error contributes to the life expectancy gap for people with severe mental illness, who on average lose a decade of life compared to the general population. Chronic physical conditions are frequently overlooked, as persistent pain or fatigue may be attributed to a psychiatric issue rather than an inflammatory condition or cancer. Failure to detect these serious conditions early means they are often diagnosed at a more advanced and less treatable stage.
The constant dismissal of genuine physical complaints can lead patients to lose trust in the healthcare system and avoid seeking necessary medical attention. This avoidance behavior ensures that potential health issues go undetected until they become medical emergencies. In some cases, a change in behavior signaling severe physical distress is misinterpreted as self-harm, leading to inappropriate treatment instead of surgical intervention.
Steps for Patients and Caregivers to Ensure Full Assessment
Patients and caregivers can mitigate the risk of diagnostic overshadowing by becoming informed advocates. Maintaining a detailed symptom journal is helpful, documenting the onset, duration, severity, and specific characteristics of any new complaint. The journal should also track corresponding changes in behavior, mood, or sleep patterns, providing objective evidence separate from the established condition.
It is important to clearly communicate that the current symptoms represent a change from the patient’s baseline health status. Caregivers should insist on a differential diagnosis, stating that the new complaint should not be automatically attributed to the existing diagnosis. This advocacy requires requesting a full physical examination and appropriate diagnostic tests, such as blood work or imaging, before accepting a behavioral explanation.
Seeking a second opinion from a specialist knowledgeable about specific co-morbidities is a practical strategy for comprehensive assessment. Bringing a trusted support person to appointments can help ensure that all concerns are communicated clearly and that the medical advice is fully understood.