Smoking cessation trials

I submit that the meta-analysis by Mark Eisenberg and colleagues on pharmacotherapies for smoking cessation¹ is grounded in a false premise, namely that researchers were somehow able to hide the onset of nicotine withdrawal symptoms from control group members, whose previous quitting history had taught them exactly how withdrawal felt (a rising tide of anxieties, anger, dysphoria, concentration difficulty and sleep fragmentation within 24 hours of quitting), and that researchers found a way to mask the reduction of withdrawal syndrome for intervention group members. Mooney and colleagues found that studies of nicotine replacement therapies are generally not blind in that participants correctly guess assignment at rates significantly above chance.² When this finding is combined with the meta-analytic finding by Eisenberg and colleagues that smoking cessation with pharmacologic treatment is nearly always more successful than cessation without pharmacologic treatment in clinical trials and the fact that cessation with pharmacological treatment has failed to be more successful than cessation without such treatment in nearly all of real-world surveys conducted to date,³ it strongly suggests that the pharmacologic treatment of chemical dependency may be the only known research area in which blinding is impossible.

Mooney and colleagues warned that the validity of the results of clinical trials of nicotine replacement therapies could be questioned if future studies failed to assess the integrity of study blinding.² This warning has not been heeded. How badly can study blinding fail? Dar and colleagues found that control group members were 3.3 times more likely to correctly guess that they had received placebo than to incorrectly guess that they had received nicotine (54.5% v. 16.4%).⁴

In the era in which pharmacologic therapies are used for smoking cessation, the decline in smoking rates seen previously has come to a screeching halt.⁵ Although excitement about varenicline should briefly improve cessation rates, Canadian policy-makers must realize that toying with chemicals that stimulate the dopamine pathway is not more effective than teaching those hooked on nicotine how to quickly and more comfortably adapt to natural stimulation.