COMT and schizophrenia: Those studies suggested that AA homozygosity, specifically in women, might be adversely associated with cognitive functioning (Gurvich and Rossell, 2015) and subcortical brain volumes (Bollettini et al., 2017), which could be also related to the association of COMT rs4680 polymorphism with treatment-resistance observed only in female patients with schizophrenia in the present study.