Keywords: prevention; HIV infection; Aids; quality control; conference; international area; health and disease; social equality; social environmental risk and protective factors; government and politics; AOD use, abuse, and dependence; cannabis; referendum; law; amendment; legal regulation; medical use of marijuana; heroin-assisted treatment; addiction care; continuing education; suicide prevention; monitoring; cost-effectiveness; gender; research; migration; hepatitis C; prevention campaign; Switzerland; Rosenbrock, Rolf; Arz de Falco, Andrea; interview