These findings allowed to stratify early psychosis patients in two subgroups: (a) patients “with mitochondrial dysfunction” characterized by exosomal high miR-137 and low COX6A2, presumably representing PV neuron dysfunction associated with mitochondria and (b) patients “without mitochondrial dysfunction” having miR-137 and COX6A2 levels within the healthy control range. The gene discussed is COX6A2; the disease is psychotic disorder.