TH and schizophrenia: Whereas midbrain TH mRNA and protein levels were unchanged between schizophrenia and controls, we observed a greater range of values in schizophrenia compared with controls in both mRNA and protein, perhaps reflecting the contradictory evidence for changes (both increases and decreases) found in previous studies.11, 16, 17, 18 Although our study contributes to the evidence suggesting there are no overall changes in TH mRNA or protein levels in midbrain in schizophrenia, it cannot rule out a change in TH activity.