Toward a test for detecting in childhood the risk of developing bipolar disorder and schizophrenia

A team from Centre de recherche Université Laval Robert-Giffard (CRULRG) has made significant progress toward finding a way to determine whether a child is likely to one day suffer from bipolar disorder or schizophrenia. The findings of the research team supervised by Dr. Michel Maziade, director of CRULRG, professor in Université Laval’s Faculty of Medicine, and Canada Research Chair in the Genetics of Neuropsychiatric Disorders, will be presented at the International Congress on Schizophrenia Research on March 31 in Colorado Springs.

Schizophrenia and bipolar disorder are problems that emerge early on in life, but that are usually not diagnosed before the age of 20 or 25. The participants in Dr. Maziade's study - a group of 45 children from families densely affected by schizophrenia or bipolar disorder - had not yet been diagnosed for the diseases. However, they came from families where the prevalence of these illnesses was 15 to 20 times higher than in the general population and, in each case, one of the parents suffered from either bipolar disorder or schizophrenia.

A battery of neurological tests revealed that these high-risk children performed much more poorly than a control group in memory tasks and executive functioning (planning, classifying, and interpreting information). “These tests show quantifiable dysfunctions in the brain of children or teenagers that could be used as early warning signs for the disease,” explains Dr. Maziade. “The ultimate goal is to use them to estimate the risk for a child as young as three or four years old and start preventative treatments.”

Schizophrenia and bipolar disorder take on many different forms and, as of yet, there are no biological tests to rapidly confirm diagnosis with certainty. About 1% of the population suffers from schizophrenia. As for bipolar disorder, it is estimated that 2.6% of people between 25 and 64 are affected by it at least once in their lifetimes.

A genetic study of 2,000 people from 46 Eastern Quebec multigenerational families severely affected by these diseases has been conducted by CRULRG since 1989. It has allowed the discovery of ten genomic susceptibility sites shared by the two diseases in the genetic make-up of the participating families. The dysfunctions revealed through neuropsychological testing also proved to be very similar whether the children were from families at risk for schizophrenia or for bipolar disorder. “The two diseases have a lot in common. One can assume they have a common origin and that something eventually happens to trigger the onset of a specific illness,” suggests Maziade.

Dr. Maziade is confident the results of this study will bring hope to those afflicted by the diseases. “Medication currently available can treat symptoms, but not the disease itself. Our results are encouraging because they give us a glimpse of the causal mechanisms and thus bring us closer to a more effective treatment. They also pave the way to better prevention because early identification of at-risk children will make it possible to help them more effectively, especially in school, where they often exhibit learning problems.”