In response to the objectives of the pilot study, here are our answers:
· The position and working processes of our treatment centers differ amongst each other (and probably also within a country). ‘Drug counseling’ including motivational 11 interviewing may be selected as common denominator for treatment as usual in the main study. However, limits should be posed on the duration of therapy – which appears to be feasible –, and some common elements of drug counseling should be defined and stressed (elements that distinguish drug counseling from MDFT).
· European therapists are trainable in MDFT and have the potential to adhere to MDFT principles. Importantly, learning MDFT is not just adding something to existing treatment repertoires. It is about fundamentally changing ways of working.
· MDFT is an evidence based method to treat multi-problem adolescents with also cannabis use disorder. The Cannabis Questionnaire we developed adequately identifies these youth. In each of our countries, there are probably sufficient numbers of these adolescents to strongly justify an implementation trial of MDFT. Recruitment of these adolescents into MDFT requires well-functioning referral networks between treatment agencies and not referring away such youth to inpatient settings.
· An INCANT main study is feasible and desirable, with possibly different levels of participation of treatment centers – to be outlined in the upcoming proposal for main study.