DRD2 and major depressive disorder: As an initial step to investigate whether the expression pattern of D2R might be altered in schizophrenia, we carried out Western blot analysis with all 60 formalin-fixed paraffin-embedded human postmortem striatal sections from the Stanley Foundation, including 15 samples from each of four groups: control, bipolar disorder (BD), major depressive disorder (MDD) and schizophrenia (SZ).