Table 1.

Measures for young cannabis users

Target variable	Measure	Point of measurement
Sociodemographics Living situation Social network Problems with school, police, debts... Education Prior counselling and therapies		pre, follow-up
Screening for acute psychosis	Subscale of the Diagnostisches Interview psychischer Störungen (DIPS; Diagnostic Interview of psychiatric disorders) [26]	pre
Substance use history	Following the assessment standards III of the DG-Sucht (German Society for Addiction Research and Therapy)	pre, post, follow-up
Severity of dependence	Severity of dependence scale (SDS) [27]	pre, post, follow-up
Psychosocial adjustment	Youth self report (participants aged 14-17) [28] Young adult self report (Participants aged 18-21) [29]	pre, post, follow-up
Expected positive and negative effects of cannabis use	Comprehensive Cannabis Expectancy Questionnaire (CCEQ) [30]	pre, post, follow-up
Relationship to friends and peers	Questionnaire for health-related quality of life (Kiddo-KINDL revised, subscale "friends") [31]	pre, post, follow-up
Family relationships	Familienbogen/Selbstbeurteilungsbogen (family inventory, self-rating) [32]	pre
Motivation for change in cannabis use	Fragebogen zur Erfassung der Veränderungsbereitschaft (FEVER; Questionnaire to protocol the willingness for change) [33,34]	pre, post, follow-up
Personal goals with regard to changes in substance use	Zielskala [35]	pre, post, follow-up
Self-efficacy with regard to cannabis abstinence or limited cannabis use	Heidelberger Skalen zur Abstinenz-/Kontrollzuversicht (HEISA-16/HEIS-KOTZ-12; Heidelberg scales of confidence regarding abstinence/controlled use) [35]	pre, post, follow-up
Satisfaction with the training	Fragebogen zur Beurteilung der Behandlung, Version Patient (FBB-P; Questionnaire for the satisfaction with treatment, patient version) with minor adaptations [36]	post
Peer resistance regarding cannabis use	own development	pre, post, follow-up