Study Underscores the Difficulty of Diagnosing Schizophrenia

By Thomas Crocker
Monday, January 6, 2020

Schizophrenia is often misdiagnosed, with potentially far-reaching consequences, but early referral to a specialty clinic for a second opinion can help alleviate the problem, according to a new study.

A psychotic disorder characterized by hallucinations and delusions, among other symptoms, schizophrenia hampers problem-solving, decision-making and emotional regulation. Schizophrenia affects 0.25% to 0.64% of people in the United States, according to the National Institute of Mental Health. Symptoms typically first appear in a person’s teens or 20s, according to the American Psychological Association.

Schizophrenia is notoriously difficult to diagnose accurately. Many clinicians lack the expertise to differentiate between attenuated psychosis symptoms — these may resemble delusions and hallucinations, but individuals retain insight that the experiences are not real — and true psychosis, including schizophrenia, according to Diana Perkins, MD, MPH, Professor in the Department of Psychiatry at the University of North Carolina School of Medicine.

“[O]nly one in five people [who experience attenuated psychosis symptoms] will develop a full-blown psychotic disorder within two to three years … so we can’t treat attenuated psychosis like psychosis, even though it kind of looks like psychosis,” she says.

Evidence of Overdiagnosis

Mistaking attenuated psychosis symptoms for psychosis may be one factor leading to misdiagnosis of schizophrenia — a phenomenon that Russell Margolis, MD, Professor of Psychiatry and Neurology, Director of the Laboratory of Genetic Neurobiology, and Clinical Director of the Johns Hopkins Schizophrenia Center at Johns Hopkins University School of Medicine, and colleagues at the university’s Early Psychosis Intervention Clinic (EPIC) began seeing with increasing frequency. They conducted a study to learn more about the drivers of schizophrenia misdiagnosis. Much is at stake.

“The goal of treatment for an adolescent or young adult with a serious mental illness such as schizophrenia is to help keep them as close as possible to the life trajectory they would have been on if they had not gotten ill — able to follow their interests in school, work and/or relationship building,” Dr. Margolis says. “An accurate diagnosis informs clinicians about the optimal treatment strategies to help patients return to that life trajectory. An inaccurate diagnosis can lead to the wrong treatment, which may hinder rather than help.”

Dr. Margolis and his team analyzed the records of 78 patients who were referred to EPIC between February 2011 and July 2017 by psychiatrists, nurse practitioners and other medical providers. Forty-three (55%) patients presented with a schizophrenia diagnosis, and clinicians at EPIC diagnosed 22 (51%) with a different disorder. Eighteen of those 22 patients (41%) were found to not have any type of psychosis. The most common factors prompting a change of diagnosis were symptoms of anxiety and the absence of thought disorder. The findings appeared in the Journal of Psychiatric Practice.

“We were … surprised by the frequency with which we [changed diagnoses for] patients who were thought to have schizophrenia or a related disorder,” Dr. Margolis says. “Based on our evaluation, the most common diagnoses for these patients was … either an anxiety or a mood disorder.”

The team suspects several factors contribute to excessive misdiagnosis of schizophrenia, including, the researchers write, “an overly literal interpretation of patients’ self-reported symptoms, especially ‘hearing voices.’” It is not uncommon for the general population and individuals with anxiety disorders to hear voices, but the experience is different for people with schizophrenia, according to Dr. Margolis. The researchers also point to widespread use of symptom checklists that lack the nuance and detail of full mental health histories, and deficiencies in the classification of psychiatric disorders as potential causes of schizophrenia misdiagnosis.

Calls for Early, Expert Consultations and More Clinician Education

For Dr. Margolis and his team, the study provides evidence that clinicians should consider referring patients with a suspected psychotic disorder to a specialty clinic as early as possible.

“Our study suggests that general child or adult psychiatrists, and especially primary care clinicians, should frequently consider a second opinion [for patients with suspected psychotic disorders],” Dr. Margolis says. “This is most necessary in ambiguous or atypical cases.”

Dr. Perkins, who was not involved with the study, advocates for more provider education about the difference between attenuated psychosis and psychosis.

“The mental health providers who treat schizophrenia all the time don’t know the difference between attenuated psychosis and full psychosis,” she says. “It’s just not something people have learned in medical school … it’s not something people are trained on in residency. It’s still an academic issue rather than a bread-and-butter clinical issue, and it needs to start turning into [a clinical issue].”