Psychosis has been related with dopamine alterations in deep brain nuclei. Neuromelanin is a by-product of the synthesis of dopamine and it is synthesized via iron-dependent oxidation. Thus, susceptibility might give a window to study the progression of dopamine levels at deep brain nuclei of psychotic patients. We studied a cohort of patients with First Episode of Psychosis (FEP) using QSM at two time points and compared them with healthy controls. We found susceptibility changes in seven subcortical areas at FEP onset. We also found susceptibility changes at the left globus pallidus interna after three months of pharmacological treatment.