In France, experts estimate that between 1% and 2.5% of the adult population suffers from bipolar. This chronic mood disorder (formerly called “manic-depressive illness”) is characterized by the alternation of two “mental phases”: the manic phase and the depressive phase.
Concretely, when the sick person is in the manic phase, he is hyperactive, euphoric and embarks on many projects. Conversely, during their depressive phase, the bipolar person feels great sadness, has no taste for anything and feels listless. Bipolar disorder is most often seen between the ages of 18 and 24. When you suffer from bipolarity, the risk of suicide is higher: 10% to 20% of patients commit the irreparable.
Scientists do not yet know exactly where bipolar disorder originates. However, in a new study, researchers at the University of Texas Health Science Center at Houston (US) put forward a new hypothesis: the size of the hippocampus. A little anatomy lesson: in the brain, the hippocampus is an area of the cortex made up of several “parts” – the serrated gyrus, the entorhinal cortex, the subiculum, and the horn of Ammon (which is itself subdivided into -units: CA1, CA2, CA3 and CA4).
The disease influences the size of the hippocampus
We now know that the hippocampus is involved in many pathologies:alcoholism, the Alzheimer’s disease, chronic 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 would be significantly less bulky than in healthy people … To reach this conclusion, the scientists conducted experiments with medical imaging techniques (MRI , notably). They discovered that type I bipolar people, in particular, had a lower 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 course of the disease would also reduce the size of CA1. A new track to follow …