Evaluation of Membrane Phospholipid and Energy Metabolism in Subjects at High Risk of Psychotic Transition

The management of schizophrenia is a major public health issue, due to its particularly disabling psychotic symptoms and their onset at an early age, typically in adolescents or young adults.

The physiopathological hypothesis of an anomaly relating to the renewal of cell membranes and energy metabolism in schizophrenia was proposed as early as the 1930s. This is based on anomalies at certain times in the development of the balance between phosphomonesters, precursors of membrane phospholipids, and phosphodiesters, catabolites of membrane phospholipids. Alterations of these different balances sign neurodevelopmental disorders, and can be objectified by specific techniques such as phosphorus-31 magnetic resonance spectroscopy (SMR-31P). This is used in particular to characterize the energy metabolism of the brain and allows in vivo quantification of phosphorus metabolites.

The application of SMR-31P techniques to assess the metabolism of membrane phospholipids and cellular energy metabolism in subjects at high risk of psychotic transition could make it possible to objectify a difference between subjects subsequently suffering from a psychotic transition compared to those who do not suffer from it. Alterations in the metabolism of membrane phospholipids could thus represent a biomarker of psychotic transition. Secondarily, this approach would make it possible to provide elements as to the validity as a diagnosis of this category, which is very heterogeneous in its future.

Among the Ultra High Risk (UHR) group, subjects with a psychotic transition (UHR-T) are compared to subjects without this transition (UHR-NT) during the two years of follow-up.

The UHR group is compared to the control group.

At T0, UHR patients and healthy volunteers will perform brain MRI with Phosphorus 31 magnetic resonance spectroscopy.

UHR patients will then be reviewed:

• at T+1 year for a clinical assessment medical interview to assess the patient's functioning and the appearance of symptoms;
• at T+2 years for the realization of a follow-up interview with passing of the scales CAARMS (Comprehensive Assessment of At Risk Mental State) and SOFAS (scale of evaluation of the social and professional functioning) in order to determine if the subject belongs to the UHR-T or UHR-NT group.