Effects of motivational interviewing on smoking cessation in adolescents with psychiatric disorders.

Objective: To test the hypothesis that among adolescent smokers hospitalised for psychiatric and substance use disorders, motivational interviewing (MI) would lead to more and longer quit attempts, reduced smoking, and more abstinence from smoking over a 12 month follow up.

Design: Randomised control trial of MI versus brief advice (BA) for smoking cessation, with pre- and post-intervention assessment of self efficacy and intentions to change, and smoking outcome variables assessed at one, three, six, nine, and 12 month follow ups.

Setting: A private, university affiliated psychiatric hospital in Providence, Rhode Island, USA.

Patients Or Other Participants: Consecutive sample (n = 191) of 13-17 year olds, admitted for psychiatric hospitalisation, who smoked at least one cigarette per week for the past four weeks, had access to a telephone, and did not meet DSM-IV criteria for current psychotic disorder.

Interventions: MI versus BA. MI consisted of two, 45 minute individual sessions, while BA consisted of 5-10 minutes of advice and information on how to quit smoking. Eligible participants in both conditions were offered an eight week regimen of transdermal nicotine patch upon hospital discharge.

Main Outcome Measures: Point prevalence abstinence, quit attempts, changes in smoking rate and longest quit attempt. Proximal outcomes included intent to change smoking behaviour (upon hospital discharge), and self efficacy for smoking cessation.

Results: MI did not lead to better smoking outcomes compared to BA. MI was more effective than BA for increasing self efficacy regarding ability to quit smoking. A significant interaction of treatment with baseline intention to quit smoking was also found. MI was more effective than BA for adolescents with little or no intention to change their smoking, but was actually less effective for adolescents with pre-existing intention to cut down or quit smoking. However, the effects on these variables were relatively modest and only moderately related to outcome. Adolescents with comorbid substance use disorders smoked more during follow up while those with anxiety disorders smoked less and were more likely to be abstinent.

Conclusions: The positive effect of MI on self efficacy for quitting and the increase in intention to change in those with initially low levels of intentions suggest the benefits of such an intervention. However, the effects on these variables were relatively modest and only moderately related to outcome. The lack of overall effect of MI on smoking cessation outcomes suggests the need to further enhance and intensify this type of treatment approach for adolescent smokers with psychiatric comorbidity.