Competence to give Informed Consent to Clinical Studies. Statement by the Taskforce on "Ethical and Legal Questions" of the Association for Neuropsychopharmacology and Pharmacopsychiatry ("Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie [AGNP]") - Nedopil, N; Aldenhoff, J; Amelung, K; Eich, F X; Fritze, J; Gastpar, M; Maier, W; Möller, H -J (Pharmacopsychiatry, 1999)