Use and Safety of Valproic Acid for Patients with Behavioural and Psychological Symptoms in a Cognitive Behavioural Unit: Retrospective Study Charlotte Rouzaud-Laborde1,2,4*, Laure Rouch1,3,4, Rigal Agathe1, Brigitte Sallerin1,2,4, Thierry Voisin3,5, Christophe Arbus6,7 and Cestac Philippe1,3,4