Most psychotropic treatments, especially AP and AD, are metabolised at the hepatic level by cytochrome P450 and in particular by CYP2D6. Duplication / multiplication of the CYP2D6 gene induces too rapid metabolism of the drugs (ultrafast metabolizer). It is linked to a clinical inefficiency of treatments, and concerns up to 10% of the general population in southern Europe (Scordo et al., 2004).