Campaigns in the media that encourage people not to take illicit drugs are now commonplace in the US, but a systematic review of the effectiveness of these interventions has not been conducted until now.

A team of researchers from Vancouver in Canada have carried out a systematic review and meta-analysis of 7 randomised controlled trials (including a total of 5,428 patients) and 4 observational studies (including a total of 17,404 patients). They evaluated all studies that assessed intention to use illicit drugs and/or levels of illicit-drug use after exposure to public-service announcements.

Here’s what they found:

• 1 randomised controlled trial showed a statistically significant benefit of public-service announcements on intention to use illicit drugs
• 2 randomised controlled trials found evidence that public-service announcements significantly increased intention to use drugs
• Their meta-analysis of randomised trials demonstrated no significant overall effect
• The observational studies they found showed a mixed picture, i.e. evidence of both harmful and beneficial effects

The reviewers concluded:

Existing evidence suggests that the dissemination of anti-illicit-drug public-service announcements may have a limited impact on the intention to use illicit drugs or the patterns of illicit-drug use among target populations.

As this area of research develops it will be interesting to see if specific media campaigns and techniques are found to be more effective at reducing drug use than others.

Werb D, Mills EJ, Debeck K, Kerr T, Montaner JS, Wood E. The effectiveness of anti-illicit-drug public-service announcements: a systematic review and meta-analysis. J Epidemiol Community Health. 2011 Oct;65(10):834-40. Epub 2011 May 10. [PubMed abstract]