How a doctor’s bias can put patients at risk

What is diagnostic overshadowing and why should patients and their families know about it?

Simply put, it’s when a doctor or nurse ignores or dismisses a patient’s symptoms because of bias. People with a history of mental illness and older people, particularly those with dementia, are most affected by it, according to Andy Lazris, a Maryland-based doctor who specializes in geriatrics and an expert on diagnostic overshadowing.

“To me, diagnostic overshadowing is that we have made our assumptions about this person already and those assumptions blind us,” Lazris said.

In November, nurses and mental health technicians at the Hospital of the University of Pennsylvania-Cedar Avenue failed to quickly render aid to a critically ill patient on the hospital’s behavioral health unit. State health inspectors released a report last week that says diagnostic overshadowing may have played a role.

» READ MORE: Nurses left patient to die at Penn Medicine hospital. State inspectors issued a severe warning.

The Joint Commission, the nation’s largest hospital-accrediting organization, issued an alert to its members in 2022 about diagnostic overshadowing, describing it as “a harm that stems from cognitive bias.” The commission warned hospitals that it can contribute to dangerous delays in diagnosis and treatment.

The commission provided an example of a 42-year-old woman previously diagnosed with mental illness who went to a gastroenterologist for nausea and stomach pain. The gastroenterologist decided the symptoms were due to her mental and emotional state and told her she’d have to “learn to live with it.”

The woman became seriously ill, and she went to a gastroenterologist at a women’s medical center who performed tests that revealed she was suffering from a bacterial infection in her small intestine. The condition, known as SIBO, causes diarrhea and malnutrition and typically requires an antibiotic.

At health-care facilities that treat patients with psychiatric disorders or behavioral health problems, bias can be more prevalent. So it’s important for providers in those facilities to be mindful of diagnostic overshadowing and take seriously any change in a patient’s condition, Lazris said.