Given clinical reports that antidepressants that block SERT, NET and DAT are therapeutically more efficacious than those that block only one or two of these transporters [49], blockade of PMAT, and potentially other D22-sensitive transporters such as OCT2 and OCT3, are deserving of further study as a useful therapeutic strategy, either as a standalone antidepressant (putatively in juveniles) or as an adjunctive treatment to existing antidepressants for sufferers of depression of all ages. This evidence concerns the gene SLC29A4 and major depressive disorder.