DRD2 and major depressive disorder: Comparison with other neurodevelopmental and psychiatric traits suggests shared genetic liability operating in specific subpopulations of GE neurons, such as the developing dopamine D2 receptor-expressing MSN, LGE-N-4 (enriched for common variant associations with autism and bipolar disorder as well as schizophrenia), and the SST-positive GABAergic interneuron, MGE-N-3 (enriched for common variant liability to bipolar disorder, major depressive disorder, and schizophrenia).