Thus, we collected data from the “bEhaVioral symptOms in Alzheimer’s disease: evaLUation of paTIents treated with chOliNesterase inhibitors” (EVOLUTION) study in order to describe changes in cognitive and affective domain severity in mild to moderate AD patients enrolled in a switch ChEI study for lack or loss of efficacy and tolerability/compliance. The gene discussed is BCHE; the disease is Alzheimer disease.