COMT and schizophrenia: While it was reported that reduced activity in the left frontotemporal and the right orbitofrontal cortex could be a critical region for the deficit in abstract thinking in schizophrenia [60], low COMT activity in healthy men, resulting from the presence of the A allele of COMT rs4680 was associated with reductions in resting blood flow in frontal regions, compared to high COMT activity groups [61].