In France, experts estimate that between 1% and 2.5% of the adult population suffer from bipolarity. This chronic mood disorder (formerly called “manic-depressive psychosis”) is characterized by the alternation of two “mental phases”: the manic phase and the depressive phase.
Concretely, when the sick person is in a manic phase, he is hyperactive, euphoric and launches into many projects. Conversely, during their depressive phase, the bipolar person feels great sadness, has no taste for anything and feels apathetic. Bipolar disorder most often reveals itself between the ages of 18 and 24. When one suffers from bipolarity, the risk of suicide is higher: 10% to 20% of patients commit the irreparable.
Scientists don’t yet know exactly where bipolar disorder originates. However, in a new study, researchers from the University of Texas Health Science Center at Houston (in the United States) put forward a new hypothesis: the size of the hippocampus. A quick lesson in anatomy: in the brain, the hippocampus is an area of the cortex made up of several “parts” – the dentate gyrus, the entorhinal cortex, the subtilum and Ammon’s horn (which itself is cut out underneath -units: CA1, CA2, CA3 and CA4).
Disease influences the size of the hippocampus
We now know that the hippocampus is involved in many pathologies:alcoholismthe Alzheimer’s diseasechronic insomnia… This small area of the brain is also frequently associated with mood and memory.
However, according to American researchers, in bipolar people, the hippocampus is significantly less voluminous than in healthy people… To reach this conclusion, the scientists conducted experiments with medical imaging techniques (MRI , particularly). They discovered that type I bipolars, in particular, had a smaller than average CA4.
“This area was significantly smaller in size in people experiencing frequent manic phases,” add the researchers, whose work has been published in the specialized journal Molecular Psychiatry. In addition, the evolution of the disease would also regress the size of CA1. A new path to follow…
