We recently explored cerebral metabolism in these MOH patients using (18F)FDG-PET (Fluoro Dexoxy Glucose Positon Emission Tomography) comparing them with controls. Results showed a hypometabolism in the OFC, which persist immediately after the antimigraine drugs withdrawal. A similar pattern is observed in varied substance related disorders and should be a marker of addictive behaviour. It can be linked with difficulties in the decision-making process, which can be explored by the Iowa Gambling Task (IGT) test.