DRD1 and Alzheimer disease: Additionally, the finding that DRD1, a GPCR coupled to Gs/α, and downstream effectors PDE1B and CAMK4 are associated with this module and the agitation domain is in line with some genetic reports that DRD1 SNPs are associated with greater impulsivity and aggression [87, 88], including in AD [89, 90] and Parkinson’s disease [91].