A recent randomized trial (Annals Int Med, epublication) found that, among smokers trying to quit, gradual cessation was inferior to abrupt cessation (6 month prolonged abstinence = 15% vs 22%) and this occurred even in smokers who preferred gradual reduction. This study was replication of our earlier trial (Drug Alcohol Dependence 111:105–113) that was more externally and internally valid and have more clear-cut results than our trial.
One possible reason why gradual was inferior is that gradual reduction requires smokers to delay quitting. Our research and that of others suggests delaying quitting does reduce success rates (J Substance Abuse Tx 46: 264-267) probably due to loss of motivation to quit over time. In fact, in the Annals study, a big part of the reason gradual did worse is because fewer smokers tried to quit in the gradual group.
Another possible reason is that the reduction in the Annals study was quite rapid; i.e., to 50% in one week and 75% by two weeks. However, two unpublished studies suggest more rapid reduction is more effective. However, this may not be the case if smokers are somewhat ambivalent for quitting. In fact the reduce-to-quit program for NRT in Europe allows 6 months to reduce before quitting.
Finally, in interpreting the Annals study, we need to remember this is a study of smokers who are actively trying to quit. Other studies show that, among smokers not currently ready to quit, gradual reduction increases later quitting (Int J Environ Res Public Health 12:10235-53). Gradual reduction appears to be good for motivating ambivalent smokers to make a quit attempt, but not good for smokers who are already motivated to quit. I would have never predicted this, but, then again, that’s why we do research.