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NIH National Institute of Mental Health transforming the understanding and treatment of mental illnesses

1/3/24 Research Highlight: Disparities in Psychotic Disorder Diagnoses and Other Negative Health Outcomes


Psychotic disorders are serious illnesses that disrupt how a person thinks, feels, and perceives the world. People with these disorders, which include schizophrenia and other disorders with psychotic symptoms, have better outcomes if they receive early and comprehensive care. Without such care, people with psychosis often find it difficult to participate in work, school, or relationships and can experience significant impairment or disability.


Studies from other countries have found demographic differences in the rates at which psychotic disorders are diagnosed. However, few studies looked at these rates in U.S. populations. New research funded by the National Institute of Mental Health (NIMH) found disparities in psychotic disorder diagnoses and showed that such diagnoses are associated with a range of negative health outcomes.


What did this study look at?


Researchers led by Winston Chung, M.D. , at Kaiser Permanente and Kathleen Merikangas, Ph.D., and Diana Paksarian, Ph.D., in the NIMH Intramural Research Program examined trends in the diagnosis of psychotic disorders in the United States from 2009 to 2019.


The study was a retrospective chart review, meaning the data were collected from patients’ existing medical records. The researchers looked at records for almost 6 million patients treated at a large health care system in Northern California. Among the information they gathered were:


  • Demographic characteristics, including self-reported race and ethnicity

  • Medical diagnoses, including psychotic disorders and other mental disorders and physical conditions

  • Negative health outcomes and behaviors, including a lack of health care use

Participants were categorized in two ways. The first was into one of seven racial and ethnic groups: African American or Black; American Indian or Alaskan Native; Asian American; Latino or Hispanic; Native Hawaiian or Pacific Islander; non-Hispanic White; or “other” racial and ethnic group, which included people who identified as multiple races or ethnicities. The second was into those who had a psychotic disorder alone (nonaffective psychotic disorder) or a psychotic disorder accompanied by symptoms of a mood disorder like bipolar disorder or depression (affective psychotic disorder).


The researchers determined the number of psychotic disorders diagnosed in each study year and compared how those rates changed over time and among different racial and ethnic groups. Additionally, they looked at whether experiencing a psychotic disorder was associated with a higher likelihood of being diagnosed with another medical condition or experiencing negative health outcomes.


What did the study results show?


Psychotic disorder diagnoses were stable (for some groups) over time.


Overall, rates of psychotic disorders remained relatively stable over the 10-year study period. In all years, nonaffective psychotic disorders were diagnosed more than affective psychotic disorders.


Black participants consistently had the highest rates of diagnosis for both types of psychosis, while Asian participants had the lowest rates. Nonaffective psychotic disorders decreased significantly among White and Asian participants over time, whereas they significantly increased for participants whose racial and ethnic group was “other.” Rates of affective psychotic disorders were consistent for all groups over time.


Psychotic disorder diagnoses differed between racial and ethnic groups.


The next set of analyses examined the probability of being diagnosed with a psychotic disorder based on racial and ethnic group membership. White participants were used as the reference group because they comprised the largest group in the study.


The data suggested disparities in diagnoses for psychotic disorders based on race and ethnicity. The patterns differed for nonaffective compared to affective psychotic disorders.


  • For nonaffective psychotic disorders, Black and American Indian or Alaskan Native participants had a higher likelihood of a diagnosis. Hispanic, Asian, and other participants had a lower likelihood of a diagnosis.

  • For affective psychotic disorders, the likelihood of a diagnosis was again higher for Black and American Indian or Alaskan Native participants as well as for Hispanic participants. The likelihood of a diagnosis was lower for Asian, Native Hawaiian or Pacific Islander, and other participants.

Psychotic disorders were associated with other health conditions and negative health outcomes.


The final set of analyses looked at associations between psychotic disorders and other health conditions and negative health outcomes. People with a psychotic disorder were more likely to be diagnosed with another mental disorder, most commonly, bipolar disorder, drug use disorder, or depression. Similarly, people with a psychotic disorder were more likely to have a comorbid medical condition, such as obesity, diabetes, and a cardiovascular disease like stroke, and to have died by suicide. People with a psychotic disorder were also less likely to have seen a health care provider in the past year—despite already being enrolled in a health care system.


Together, these results emphasize the pervasive and serious health risks posed by having a psychotic disorder, resulting in poorer mental and physical health and increased risk for premature death. Combined with evidence for racial and ethnic disparities in rates of psychotic disorders, the findings emphasize the disproportionate health impacts faced by particular groups in the United States.


What do the results tell us?


This study is noteworthy for collecting comprehensive clinical data from a large registry of diverse Americans over an extended period. However, the sample came from one health care system in a single U.S. state, so the results may not generalize to rates of mental illnesses in other parts of the country. It will be useful to replicate the results in additional samples.


Nonetheless, the results confirm a high health burden associated with psychotic disorders, including a range of co-occurring mental and physical conditions and preventable causes of death. Patients with a psychotic disorder were also far less likely than patients without a disorder to seek health care.


Importantly, rates of psychotic disorders—and their associated health risks—were not distributed equally among racial and ethnic groups. And, although rates of psychotic disorders were mostly stable over time and even decreased for some groups, this trend was not seen across all groups.


Moreover, several of the identified disparities were for affective psychotic disorders. This finding emphasizes the importance of training health care providers to recognize mood disorders and manage the full range of psychotic and affective symptoms their patients may experience.


What can researchers and clinicians do next?


According to the researchers, these findings suggest several avenues for future research. First, having identified disproportionally higher or rising rates of psychotic disorders among specific racial and ethnic groups, researchers could examine factors driving these disparities and whether they can be reduced by tailoring care or prevention efforts to specific populations. Moreover, this study used broad racial and ethnic categories (for instance, Asian), which may have masked differences for individual subgroups (for instance, Chinese, Filipino). Exploring whether patterns of diagnosis are the same within racial and ethnic categories would add important information to our understanding of disparities as it relates to psychotic disorder diagnoses.


It is also important to determine whether the data reflect true differences in the rates at which people are experiencing psychotic disorders in the United States. There are possible unmeasured factors that might have influenced the results. For clinicians, these include misdiagnosis and unconscious biases, such as a greater willingness to diagnose certain groups with a stigmatized condition. Moreover, there are known differences in treatment access, health care knowledge, and quality of care between racial and ethnic groups that may have affected their likelihood to seek out and receive effective mental health care.


To fully understand and address disparities in psychotic disorders in this country, more comprehensive, prospective studies are needed that assess a broad range of influences and outcomes. Among the factors future studies could look at are socioeconomic status, adverse childhood events, experiences of interpersonal and structural racism, and social determinants of health.


Reference

Chung, W., Jiang, S.-F., Milham, M. P., Merikangas, K. R., & Paksarian, D. (2023). Inequalities in the incidence of psychotic disorders among racial and ethnic groups. American Journal of Psychiatry, 180(11), 805–814. https://doi.org/10.1176/appi.ajp.20220917 

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