Postnatal neurogenesis and dopamine alterations in early psychosis

Schizophrenia is most likely a neurodevelopmental disorder with a characteristic delayed onset of symptoms occurring usually during transition from adolescence to adulthood. Recent studies revealed that both genetic and environmental risk factors for the disease disturb not only embryonic, but also postnatal neurogenesis, possible contributing to neurochemical alterations associated with schizophrenia. Several recent patents proposed therapeutic interventions in schizophrenia by increasing postnatal neurogenesis. It remains, however, unclear, how such pro-neurogenic interventions could ameliorate alterations in neurotransmitter systems associated with the disease, such as the dopamine system. Here we review these patents in the context of the existent data about postnatal neurogenesis in the subventricular zone in rodents and primates. We discuss also in light of a recently proposed theoretical model the possible relevance of disturbed neurogenesis for the dopamine system, focusing on the dopamine receptors associated with neurogenesis, the D3 receptors, and a D3-expressing structure derived from the subventricular zone, the Islands of Calleja. Finally, we discuss these findings in the light of molecular imaging studies in early schizophrenia.