SLC6A3 and schizophrenia: The mesolimbic DA hypothesis of schizophrenia originated from clinical observations that symptoms of patients with seizure locus in the midbrain were similar to those of schizophrenia, the fact that amphetamine (a DA transporter blocker) induces schizophrenia-like symptoms, and the fact that blockers of DA D2 receptors (neuroleptics) alleviate symptoms of schizophrenia patients, especially positive symptoms (Davis et al., 1991; McCutcheon et al., 2019).