Evidence-Based Reviews

How to avoid ethnic bias when diagnosing schizophrenia

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Is your practice bias-free? Examining the misdiagnosis of African-Americans yields insights into how to avoid cultural misunderstandings.


 

References

In patients with psychotic symptoms, why are African-Americans more likely than whites to be diagnosed with schizophrenia? After more than 30 years of debate, some answers—and remedies for the problem—are becoming clear.

In psychiatry, where interpersonal interactions are key to eliciting diagnostic symptoms and signs, there is an intrinsic risk of misinterpretation when clinician and patient are of different cultural, ethnic, or socioeconomic backgrounds. This article analyzes four factors that contribute to misinterpretation and to ethnic misdiagnosis of schizophrenia. Culturally sensitive strategies are offered to avoid diagnostic bias in clinical practice.

SCHIZOPHRENIA MISDIAGNOSIS

Large epidemiologic studies report similar rates of schizophrenia and bipolar disorder in African-American and white populations.1 Although patients of both races have been wrongly diagnosed with schizophrenia, the pattern is stronger and more persistent in African-Americans.

Box 1

Diagnostic criteria for schizophrenia: Characteristic symptoms (Criterion A)

Two (or more) of the following, each present for a significant portion of time during a 1-month period (or less if successfully treated):

  • Delusions
  • Hallucinations
  • Disorganized speech (eg, frequent derailment or incoherence)
  • Grossly disorganized or catatonic behavior
  • Negative symptoms (ie, affective flattening, alogia, or avolition)

Note: Only one Criterion A symptom is required if delusions are bizarre or hallucinations consist of a voice keeping up a running commentary on the person’s behavior or thoughts, or two or more voices conversing with each other.

295.30 Paranoid type

A type of schizophrenia in which the following criteria are met:

  1. Preoccupation with one or more delusions or frequent auditory hallucinations
  2. None of the following is prominent: disorganized speech, disorganized or catatonic behavior, or flat or inappropriate affect.

Source: DSM-IV-TR

In the 1970s, Simon et al2 studied 192 hospitalized patients, of whom all African-Americans and 85% of whites had been identified clinically as having schizophrenia. Using a structured interview, the researchers found that only 40% of the African Americans and 50% of the whites met diagnostic criteria for schizophrenia. African-Americans with mood disorders were found to be at particular risk of schizophrenia misdiagnosis.

In the 1980s, among 76 patients with a clinical diagnosis of schizophrenia, Mukherjee et al3 diagnosed one-half (52%) with bipolar disorder using a structured clinical interview. Schizophrenia misdiagnoses were more common in African-Americans (86%) and Hispanics (83%) than in whites (51%). In particular, African-Americans were most likely to be misdiagnosed with paranoid schizophrenia. African-Americans complained more commonly than whites of auditory hallucinations, which may represent an ethnic difference in symptomatic presentation of psychotic mood disorders.

In the 1990s, colleagues and I conducted two studies—one of 173 patients in a Tennessee psychiatric hospital4 and the other of 490 patients in an Ohio psychiatric emergency service5—and found yet again that African-Americans were more likely than whites to be diagnosed with schizophrenia. In the hospital study, higher rates of schizophrenia diagnosis were associated with lower rates of mood disorder diagnosis. This inverse relationship implied that African-Americans with mood disorders were being misdiagnosed with schizophrenia.

Men were more likely than women to be diagnosed with schizophrenia, suggesting that African-American men were most likely to be misdiagnosed. When adjustments were made for gender, black women were found to be at higher risk for misdiagnosis than white women.

Lawson et al6 extended this research in a population-based study of African-Americans living in Tennessee. They found that African-Americans constituted 16% of the state’s population but 48% of psychiatric inpatients diagnosed with schizophrenia and 37% of psychiatric outpatients.

CONSEQUENCES OF INACCURATE DIAGNOSIS

Differentiating between schizophrenia (Box 1) and a psychotic mood disorder (Box 2) is more than a semantic exercise. Schizophrenia implies a chronic, unremitting, debilitating illness that worsens over time. Though this perception of schizophrenia is not entirely accurate, in clinical practice its diagnosis imparts a bleak prognosis that may lower the clinician’s expectations for the patient.7

Schizophrenia misdiagnosis also may lead the psychiatrist to rely excessively on antipsychotics, rather than attempting thymoleptic and psychotherapy trials. Studies suggest that African-American patients are more likely than similar white patients to receive antipsychotics4,8,9 and less likely to receive psychotherapy.5,10

Reasons why African-Americans are often misdiagnosed with schizophrenia remain unclear but probably include four contributing factors:

  • differences in symptom presentation compared with whites
  • failure by clinicians to identify affective symptoms in African-Americans
  • minority patients’ wariness when dealing with health services
  • and racial stereotyping.

DIFFERENCES IN SYMPTOM EXPRESSION

African-American patients with mood disorders or schizophrenia are more likely than are similar white patients to complain of auditory hallucinations.11-13 For example, Strakowski et al14 examined 330 patients with nonaffective and psychotic diagnoses in a study that was used to develop DSM-IV criteria for schizophrenia. Auditory hallucinations were rated as more severe in African-American than in similar white patients.

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