Table 1

Characteristics of included studies

StudyUnderpinning theoryDesign (goal)Intervention ComparisonPrimary outcomeSecondary outcome(s)Analysis sampleFollow-up (total time) (months)
Polansky et al 199925Decision theoryRCT (E)PSAOtherIntention to use; attitudes; knowledge and disposition to select socially appropriate responses312NA (NS)
Miller et al 200020Self-regulation theoryCBA (F)PSA; printedNo interventionUse of drugs (incl. cannabis and cocaine)Risk perception; problems related to drug use102412 (18)
Palmgreen et al 200124Influence of sensation-seeking on drug useITS (F)PSANo interventionPast 30-day use of marijuana6371NA (32)
Yzer et al 200326Theories of behavioural change: persuasion effectsRCT (E)PSANo intervention; otherIntention to use marijuana; attitude; perceptions about marijuana418NA (NS)
Slater et al 200610Social-ecological framework (norms and expectations influence drug use)RCT (E)PSA; printedNo interventionLifetime and past 30-day use of marijuana421624 (42)
Zhao et al 200627Normative beliefsRCT (E)PSANo interventionIntention to use; beliefs towards marijuana; social norms435NS (NS)
Hornik 200622UnclearCohort (F)PSA; printed; internetLower exposureLifetime, past year, and past 30-day use of marijuanaIntention to use; attitudes and self-efficacy; perceptions and social norms811756 (58)
Scheier and Grenard 201023Social marketingCohort (F)PSA; printed; internetLower exposurePast 12-month cannabis intoxications2515NA (48)
Schwinn et al 201019Social learning theoryRCT (E)InternetNo interventionPast 30-day substance use2366 (NS)
Lee et al 201028Readiness to changeRCT (E)InternetNo interventionPast 90-day use of marijuanaIntention to change marijuana use; consequences3416 (NS)
Fang et al 201018Family-orientedRCT (E)InternetNo interventionPast 30-day use of marijuanaIntention to use marijuana2166.25 (16)
Newton et al 201011Social influence approachRCT (E)InternetOtherUse of cannabisCannabis knowledge; attitudes; related harms72412 (21)
Meth Project studies12–16Perception of risk and perception of social disapproval are correlated with drug consumption4 ITS and 1 CBA (F)PSA; printed; internetNo interventionPast 30-day use of methamphetamineAttitudes on methamphetamine and other drugs; perceptions; information sources and advertising awareness;26 405NA
(Colorado 26; Georgia 18; Hawaii 25;
Idaho 40; Wyoming 34)
Slater et al 201121Autonomy and aspiration perceptions as mediators of marijuana useRCT (E); Cohort (F)PSA; printedLower exposureLifetime, past 90-day and past 30-day use of marijuanaAutonomy and aspiration inconsistent with marijuana use323624 (42)
Carpenter and Pechmann 20112Unclear; evaluated many heterogeneous mass-media campaignsITS (F)PSA; printed; internetLower exposurePast 30-day and lifetime use of marijuana130 245NA (36)
  • CBA, controlled before and after; Cohort, prospective cohort; E, experimental/efficacy setting; F, field/effectiveness setting; ITS, interrupted time-series; Lower exposure, lower exposure to same intervention; NA, not applicable; NS, not specified; Other, other intervention or different combination of same intervention; PSA, public service announcement (eg, television/radio); RCT, randomised controlled trial.