Researchers have found differences between the brains of people from families with a history of schizophrenia or bipolar disorder. Ultimately, this discovery could help prevent the development of these mental illnesses.
Millions of people suffer from psychoses around the world. If schizophrenia is the best known mental illness, psychotic episodes can, among other things, occur in the context of a manic episode in a bipolar person. Thus, health professionals often struggle to distinguish the two diseases in a patient in crisis. However, Dutch researchers have found differences between the brains of people from families with a history of schizophrenia or bipolar disorder. The results of their study were published this Tuesday, August 20 in the journal Biological Psychiatry. Ultimately, this discovery could help to more effectively prevent the risk of developing mental illness.
Schizophrenia and bipolar disorder are genetic diseases. Thus, members of the same family share risk factors and exposure to life events may or may not increase the risk of developing the disease. “We were interested in the relationship between this increased risk of schizophrenia and bipolar disorder and brain development,” says Sonja MC de Zwarte, lead author of the study from the University of Utrecht Medical Center in the United States. -Low.
The researchers were thus able to observe that relatives of patients with bipolar disorders had larger intercranial volumes, while relatives of schizophrenics had smaller brain volumes compared to participants from families without a history of mental disorders. Thus, “this may imply that the neurodevelopmental trajectories leading to brain abnormalities in schizophrenia or bipolar disorder are distinct,” the researchers note.
Better understand how disease risk affects the brain
“The size of the intracranial volume is considered a marker of early brain development. Thus, our results suggest that the familial risk of these disorders influences brain development from the beginning of life, and in a different way”, develops Zwarte.
The researchers also found differences in brain abnormalities depending on the degree of parenthood with a patient. With first-degree relatives sharing about 50% of their genes, environmental risk factors also contribute to brain abnormalities in family members.
Thus, this study, the largest ever carried out on the subject, demonstrates the interest of studying the relatives of people with psychiatric disorders to better understand how the risk of disease affects the brain. Ultimately, this approach could help prevent the development of mental disorders, the researchers hope.
“The potential significance of these categorical distinctions”
For John Krystal, MD, Editor-in-Chief of Biological Psychiatry, differences in brain development between disorders will be an important factor to consider in future brain imaging studies of psychiatric disorders. “The recent emphasis on dimensional features of cross-diagnosis of psychiatric disorders has de-emphasized important complementary categorical distinctions. This genomic imaging study reminds us of the potential importance of these categorical distinctions,” he concludes.
At present, schizophrenia affects around 0.7% of the world’s population, including 600,000 people in France. According to Inserm, it most often occurs in adolescence, between the ages of 15 and 25. In 35% to 40% of cases, it is manifested by acute beginnings, with delirious puffs. In addition to delusions and hallucinations, patients tend to isolate themselves, to talk incoherently and to be completely unable to plan simple tasks, which makes their daily life extremely difficult.
Bipolar disorders, on the other hand, are part of mood disorders in the same way as recurrent depression. In its most typical form, the disease has two phases: the manic phase (the subject is hyperactive and euphoric) and the depressive phase (the subject is slowed down and tastes nothing). “In France, bipolar disorders are under-diagnosed. It takes on average 10 to 12 years and four to five different doctors before they are appointed. Similarly, it is estimated that 40% of depressives are actually bipolar who ignore each other”, warns the site bipolar-disorders.com.
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