When Depression Isn’t Depression: New Study Highlights Diagnostic Gaps in Hospital Care

Although depression and delirium are both common findings in hospitalized patients, distinguishing between the two remains a persistent challenge for nonpsychiatric clinicians. A new multisite study led by Cleveland Clinic researchers is shedding light on how often these conditions are misidentified — and why those errors matter for patient care.

Published in the Journal of Psychosomatic Research, the retrospective chart review examined nearly 1,000 inpatient referrals made to consultation-liaison (CL) psychiatry services for suspected depression or delirium. Researchers compared the referring medical or surgical teams’ presumptive diagnoses with final diagnoses made by CL psychiatrists after conducting a comprehensive psychiatric evaluation.

“Our goal was not to criticize referring teams, but to better understand where diagnostic mismatches occur and what factors might be driving them,” explains Cleveland Clinic psychiatrist Molly Howland, MD, noting that both depression and delirium can present in overlapping and subtle ways in medically ill patients.

The study, which paints a nuanced picture of diagnostic accuracy, found that primary medical and surgical teams were better at identifying delirium than depression. Diagnostic agreement between primary services and CL psychiatry was 88% for delirium, compared with 67% for a strict diagnosis of depression. When the definition of depression was broadened to include adjustment disorders — a common stress-related diagnosis in hospitalized patients — agreement rose to 80%.

Dr. Howland, lead author of the study, highlights the importance of this distinction. “Although many patients present with clear signs of emotional distress, their symptoms don’t always meet the criteria for major depression,” she explains. “Primary teams are often picking up on a very real problem, even if the specific diagnosis differs.”

Key findings

Among the study subjects who were referred for depression but ultimately did not receive a psychiatric diagnosis of depression, nearly half were determined to have an adjustment disorder. Other final diagnoses included anxiety disorders, delirium and neurocognitive issues. Only 16% of patients were determined to have delirium masquerading as depression — a lower incidence than reported in earlier studies.

This relative diagnostic improvement may reflect a growing awareness of delirium in hospital settings, Dr. Howland notes, as routine orientation checks and nurse-led delirium screening tools (e.g., Confusion Assessment Method) have become more widespread.

“The symptoms of delirium have become more apparent to frontline teams, and that visibility likely contributes to better detection,” she notes.

Interestingly, younger patients were more likely than their older adults to be labeled as depressed when they were not. For every 10-year increase in age, the odds of being misdiagnosed with depression were reduced by up to 20%.

This finding suggests that targeted geriatric education may be paying off, Dr. Howland says.

“In the past decade, there has been a concerted effort to teach clinicians how psychiatric conditions present in older adults,” she says. “Our data suggest that the message may be landing.”

A prior psychiatric diagnosis also reduced the likelihood of depression overdiagnosis, implying that clinicians appropriately consider psychiatric history as a meaningful risk factor rather than a source of confusion. However, the opposite was true for patients taking psychotropic medications, in whom delirium was more than twice as likely to be misdiagnosed as depression.

“This was one of our most striking findings,” Dr. Howland explains. “Medication lists can unintentionally bias clinical thinking. Seeing an antidepressant or antipsychotic on a chart – even if it was originally prescribed for a complaint like nausea or insomnia – may lead clinicians to anchor on a psychiatric explanation. Unfortunately, this is a diagnostic shortcut that can lead providers to miss the signs of delirium and neglect to address its reversible causes.”

Importantly, the study found no significant differences in diagnostic accuracy based on sex, race or whether the referring service was medical or surgical. These results suggest that misdiagnoses may be more closely tied to clinical context and cognitive bias than to demographic factors, she adds.

Looking ahead

Dr. Howland emphasizes that the research findings should be viewed as an opportunity rather than a failing.

“Nonpsychiatric clinicians are clearly recognizing psychological distress more than they did in the past,” she says. “The next step is refining how we differentiate among depression, anxiety, adjustment reactions and delirium — especially in complex hospital environments.”

Looking ahead, the authors call for research that directly assesses clinicians’ knowledge and attitudes about psychiatric conditions, as well as studies that differentiate between delirium subtypes. Hypoactive delirium, which often presents as withdrawal or low mood, remains particularly difficult to detect, Dr. Howland adds.

“I encourage medical educators to focus on avoiding diagnostic anchoring and maintaining a broad differential,” she says. “When we get the diagnosis right, we reduce stigma, treat the underlying condition more effectively, and ultimately improve patient outcomes.”