OPRM1 and obesity due to melanocortin 4 receptor deficiency: Positive correlations between DRD2 and MOR availability using 11C‐raclopride and 11C‐carfentanil BP were reported in the ventral striatum and caudate but not in the putamen in lean participants, and in severe obesity the correlation in the ventral striatum was attenuated, suggesting aberrant mesolimbic dopamine–opiate interaction in obesity.195