A Response to the New York Times: Understanding Psychosis in African Americans

The New York Times Magazine recently ran an insightful article examining a striking trend in America. As NYT Magazine contributing writer Daniel Bergner writes in the piece, “Black people in the United States suffer the hallucinations and delusions of psychosis … at a rate roughly twice that of white people.” Through its African Ancestry Neuroscience Research Initiative, the Lieber Institute for Brain Development has been examining the genetic roots of mental illness in people of African ancestry. Now, AANRI Co-Founders Rev. Alvin C. Hathaway, Ph.D., and Daniel Weinberger, M.D., have a thoughtful response to the New York Times.

The Intersection of Genes, Racism, and Mental Health: Understanding Psychosis in African Americans

by Rev. Alvin C. Hathaway, Ph.D., and Daniel R. Weinberger, M.D.

Daniel Bergner’s story about psychotic experiences (i.e. hallucinations and delusions) in individuals of African ancestry is a compelling statement about the personal psychological impact of racial stress in our society. Hearing of voices, having ideas of persecution, personalizing race in a negative context and inequalities in the provision of mental health services are irrefutable realities for too many individuals in minority groups. These stories challenge not only our standards of social fairness and equality, but they also challenge science to uncover the causes and consequences of psychotic experiences. In an effort to parse the roles of genes and the environment (nature v. nurture) in mental illness in American individuals of African descent, a partnership was formed in Baltimore four years ago called the African Ancestry Neuroscience Research Initiative. The founding partners included the Lieber Institute for Brain Development, a nonprofit brain research institute on the Johns Hopkins Medical Campus, faith-based leadership in Baltimore, and Morgan State University, one of the country’s leading HBCUs. The goal was to level the playing field in brain research that had focused almost entirely on individuals of European Ancestry, though as Mr. Bergner notes, some brain disorders, including psychosis, may be diagnosed more frequently in African Americans.

The work of AANRI has begun to peel the cover off some of the mystery surrounding why certain brain disorders show variable prevalences in different groups. Studying how genes are turned on and off (i.e. expressed) in brains donated for medical research by African American families, we have begun to solve some of these riddles. We examined the brains of African Americans who were healthy at the time of death. Because African Americans tend to be of mixed ancestry, having on average 20% of their ancestors of European origin, it is possible to determine how much of the differences in each individual’s brain is because of their proportion of African ancestry or of European ancestry lineages. Our genome, our DNA, is a mosaic of our individual ancestral trees, with generations of our ancestors contributing pieces of their DNA to what is our individual genomes. In a report published as the cover of the June issue of Nature Neuroscience, we show that genes expressed based on an individual’s proportion of African ancestry can explain some of the disparities in brain illnesses in African Americans, including in Alzheimer’s disease and Parkinson’s disease. Remarkably, however, we found no evidence that schizophrenia, or depression or other behavioral traits were more likely to occur based on African compared with European ancestry.

While scientific research over the past decade has shown conclusively that the genes that we inherit from our parents are the principal factors that determine our risk for most psychiatric disorders, the AANRI results raise several issues. If the difference in prevalence of psychosis between racial groups is not because of genetic biases in our brains, then the environment must be playing an important role—genes are not enough. Common medical illnesses, including mental illnesses, are the result of genes and the environment interacting with each other to determine one’s probability of illness. Environments vary between people just as genes do and our genes determine one’s sensitivity to environmental experience. No particular environment guarantees depression or psychosis or diabetes or stroke in everyone, likely because some people are genetically resilient while others are genetically more vulnerable. 

To better understand the role that the environment plays, we need to evaluate environmental factors in the context of genetic factors. This is scientifically challenging to do. One example of recent progress in this effort is evidence that complicated pregnancies, which are more common in American individuals of African ancestry, interact with genes that increase risk for schizophrenia and may together raise risk more than fivefold compared to genes or complicated pregnancies alone. This result supports other scientific evidence that early brain development is a crucial determinant of a developmental trajectory that leads to psychosis.

So, what can we make of the apparent relationship of psychosis to the stresses and traumas of racism? There are three possibilities for how they are related: 1) racism may be causative of psychosis; 2) the experience of racism may exaggerate the effect of the genes that increase risk of psychosis, and 3) there may be no real relationship, perhaps because, as Daniel Bergner notes, there may be biases in diagnostic practices. While the latter possibility cannot be conclusively dismissed, the weight of the evidence he reviews suggests that this does not explain the entire relationship. As for the first possibility, it also seems unlikely because while the experience of racism is not unusual in the African ancestry community, the experience of psychosis is. What about the role of genes? Based on the AANRI brain research results, genes turned on in the brain based on African ancestry do not bias individuals of African ancestry to greater risk of psychosis than individuals of European ancestry. In other words, genetic background by itself does not explain the prevalence discrepancies. However, while the genes do not favor one group or another, the experience of racism clearly does. The conclusion is thus unavoidable that the effects of genetic predisposition for psychosis found in all communities is exaggerated in the African ancestry community because of the stresses and traumas of racism that specifically target this community.

The African Ancestry Neuroscience Research Initiative (AANRI) has taken groundbreaking steps to uncover how genetics and environment interact in shaping brain health. These findings underscore a powerful truth: while we cannot change our genetic inheritance, we can change the environments that foster inequity and amplify risk.