Table 2.

Overview of variable constructs

General life skills	Substance use (smoking and alcohol)	Additional/confounders
Communication27,28	Smoking-related and alcohol-related knowledge	Sociodemographic characteristics29
Self-esteem30	Use of tobacco31,32	General parenting style*33
Self-efficacy28	Use of alcohol34	Personality characteristics*35,36
Self-concept27	Intentions and attitudes and normative expectations37	Leisure time behaviour38
Empathy39	Susceptibility40	Class climate†
Emotions41	Resistance skills42	Bullying43,44
Stress45	Social influence32,46
Problem solving27	Perceived parental rules and attitudes47,48

^*Assessed at first post-test.

^†On the basis of own previous research.