The identification of biomarkers of ultra-resistance (UR) to treatment in schizophrenia would allow earlier, better adapted and more effective personalized management of these patients, which would improve their functional prognosis.
An early decrease in functional connectivity (FC) between some rest networks has recently been proposed as an UR biomarker by McNabb et al. Nevertheless, clozapine has, among its side effects, a direct cardiac action that profoundly modifies patient's hemodynamics. However, functional brain imaging techniques are based on BOLD effect which is dependent on these hemodynamic parameters. It is therefore not possible to say whether these differences in FC are inherent to the pathology or whether they are related to clozapine instauration which causes hemodynamic changes that may disturb BOLD signal.
To objectify UR biomarkers, investigators propose a longitudinal follow-up of resistant patients, starting before clozapine instauration and including a multimodal brain imaging assessment (T1 and T2 weighted sequences, DTI, ASL-Perfusion, fMRI- Rest) associated with clinical and biological monitoring. In order to correct the MRI signal of clozapine hemodynamic effects, investigators will develop a new MRI methodology based on the concomitant collection of physiological parameters (blood pressure, electrocardiogram and respiration).
