[1] Univ Nijmegen, Nijmegen Inst Scientist Practitioners Addict, Dept Clin Psychol & Personal, Nijmegen, Netherlands
[2] Univ Maastricht, Ctr Qual Care Res, Dept Gen Practice, NL-6500 HE Nijmegen, Netherlands
[3] Dutch Fdn Smoking & Hlth, The Hague, Netherlands