Researchers at UNIGE have discovered that the development of the hippocampus, the area of the brain responsible for memory and emotions, is severely impacted in adolescence following the onset of the first psychotic symptoms. “It’s now known that schizophrenia is linked to the hippocampus, a complex area of the brain that carries out a vast amount of processes simultaneously linked to memory, imagination and the emotions” explains Stephan Eliez, professor in the Department of Psychiatry in UNIGE’s Faculty of Medicine “That’s why we studied the development of this structure in detail, so we could understand why some people affected by deletion syndrome eventually develop psychotic symptoms, while others don’t”.

The Geneva team has been following 275 patients aged 6 to 35 years for 18 years: a control group of 135 individuals – i.e. individuals without genetic problems – and 140 people with deletion syndrome, including 53 with moderate to severe psychotic symptoms. “They underwent an MRI every three years so that we could observe their brain development,” says Valentina Mancini, a researcher in UNIGE’s Department of Psychiatry. “This has helped us create a statistical model that measures and compares the development of the hippocampus in both groups of patients.”

The study suggests the following hypothesis: the small size of the hippocampus in patients with 22q11 deletion syndrome is defined in the mother’s womb, probably due to poor vascularisation. However, a “second hit” later in development might determine the further hippocampal atrophy and the emergence of psychotic symptoms. As the critical period for schizophrenia is adolescence, the Genevan team is now working on the possibility of preventing the atrophy of the hippocampus in order to preserve its functions.

UnigeNature

Photo SE: Sub-field of the hippocampus in young male with deletion syndrome and psychotic symptoms. Atrophy of the head of the hippocampus is evident.