TH and schizophrenia: Although currently there is no evidence for an activity-dependent role for local TH synthesis, a recent post-mortem study assessing anomalies of the dopaminergic system in schizophrenia showed that TH protein levels were abnormal in schizophrenia, while mRNA expression levels were not affected, indicating that TH pathology in the substantia nigra/ventral tegmental area may occur post-transcriptionally (Perez-Costas et al., 2012).