Growing Up in Poverty Increases Diagnoses of Psychosis-Spectrum Mental Illnesses

University of California, Davis, and Concordia University, Montreal, Study Followed Families for Three Decades

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Quick Summary

  • Mental illnesses such as schizophrenia, bi-polar disorder, double in poor areas
  • While heredity is a major factor, environment plays a role
  • Childhood social behaviors are strong predictors of psychotic illnesses
  • Study suggests prevention is possible

Growing up in impoverished urban neighborhoods more than doubles your chances over the average person of developing a psychosis-spectrum disorder by the time you reach middle adulthood, according to a new UC Davis and Concordia University study of nearly 4,000 families who were monitored over 30 years.

The results of the study suggest that intervention through social policies and investment in neighborhood improvements, as well as identifying those most in need of help by observing certain child behaviors, could prevent future debilitating illnesses and the societal and personal costs associated with them, said the study’s authors.

“One important message to take from this study is that the stresses and chronic day-to-day challenges of living in under-resourced or impoverished communities can undermine the well-being of individuals whether they seem to have a vulnerability or not,” said Paul D. Hastings, professor in the Department of Psychology at UC Davis and the lead author of the paper. He explained that while heredity is a major factor in predicting schizophrenia, bipolar disorder and other disorders involving psychoses ­— that is, breaks with reality, like delusional beliefs and hallucinations — this study provides clear evidence that environmental factors experienced in childhood also affect future mental health.

The study, “Predicting psychosis-spectrum diagnoses in adulthood from social behaviors and neighborhood contexts in childhood,” was published April 24 in the journal Development and Psychopathology. Hastings conducted this study with co-authors Lisa Serbin, Dale Stack, William Bukowski, Daniel Dickson and Alex Schwartzman of Concordia University, Montreal, Canada; Jon Helm of San Diego State University; and Jane Ledingham of the University of Ottawa in Ottawa, Canada.

The origins of the Concordia Longitudinal Research Project date back to the 1970s, when the initial researchers, Ledingham and Schwartzman, sought to test existing theories on the roles of early adversity and children’s social characteristics on the development of psychiatric disorders.

The researchers followed families living in low-income urban communities in French-speaking parts of Montréal, Québec, comprising, in the end, nearly 11,000 individuals. Peer reports of behavior at school were used to assess children’s aggression, withdrawal and likeability. Beginning in the mid 2000s, Hastings, Schwartzman and their colleagues began reviewing the previous three decades of individual medical records for the family members and census data on neighborhood economic conditions. On average the children were about 10 years old at the start of the study, and were followed until they were 40. During the same period, their parents aged from their late 30s into their late 60s. Residents of Québec receive government-funded health care, and the researchers were able to analyze numerically coded records of the subject families in order to identify psychiatric diagnoses.

"...improving neighborhood conditions for all families in economically disadvantaged communities, and working directly with the families of children showing risky profiles of behavior, could improve the quality of people’s lives and markedly reduce health care costs.”

Because the researchers were able to identify parental diagnoses in the sample studied, their analyses were able to predict the children’s future prevalence of psychiatric disorders above and beyond what would result from heredity, Hastings said. More than 6 percent of the children had developed schizophrenia, bipolar disorder with psychosis, and other psychosis-spectrum disorders by middle-adulthood, and those children who grew up in the most economically disadvantaged neighborhoods had the greatest likelihood of being diagnosed with schizophrenia or bipolar disorder.

The study also found childhood social behaviors to be strong predictors of psychotic illnesses. In particular, children who were evaluated by their peers as both highly aggressive and highly withdrawn were likely to develop psychosis-spectrum disorders if they also grew up in more impoverished neighborhoods. “This hypothesis was one of the reasons that Dr. Schwartzman and Dr. Ledingham started this study in 1976, and to my knowledge, this is the first prospective longitudinal study that shows that these combined characteristics of aggression and withdrawal predict future psychosis spectrum disorders,” Hastings said.

He said these findings suggest that intervention with young children exhibiting these complex patterns of antisocial behavior could improve outcomes.

The study could help improve efforts to predict, identify and prevent serious mental illnesses, he said. “Once psychosis spectrum disorders take hold they are difficult to treat. It is kind of like ALS (amyotrophic lateral sclerosis) and similar illnesses,” Hastings added. “Disorders like schizophrenia really become chronic diseases that require constant care, management, and maintenance. Reducing them by improving neighborhood conditions for all families in economically disadvantaged communities, and working directly with the families of children showing risky profiles of behavior, could improve the quality of people’s lives and markedly reduce health care costs.”

This research was partially supported by a grant from the Canadian Institutes of Health Research. The writing of this manuscript was supported by the UC Davis Center for Poverty Research, UC Davis Center for Mind and Brain, and the Centre for Research in Human Development at Concordia University. The study was made possible by the Commission d’accès à l’information of Québec (no. 07 08 71), the Québec Health Insurance Agency, and the Ministries of Health and Education of Québec.

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