Gender-Related Differences in Hypnosis-Based Treatments for Smoking: A Follow-up Meta-Analysis

American Journal of Clinical Hypnosis,  Jan 2008  by Green, Joseph P,  Lynn, Steven Jay,  Montgomery, Guy H

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Abstract

In an earlier meta-analysis of 12 studies using hypnosis-based treatments for smoking cessation, we provided preliminary evidence that males fare better than females when trying to quit smoking (Green, Lynn, & Montgomery, 2006). By excluding studies that reported no gender differences, but failed to report final outcome-statistics-by-gender, our previous conclusion may have overestimated the role of gender in hypnosis-based smoking cessation treatment. In the present analysis, we included 12 additional studies that reported no gender differences, but failed to report final outcome-by-gender statistics. Across each of these studies, we calculated identical success rates for male and female participants and men added these results to our database. Among all 24 groups of participants who completed hypnosis-based treatment for smoking, we found a small but significant effect for male participants being more successful in quitting smoking relative to females. Specific suggestions for tailoring hypnosis smoking cessation programs to take gender differences into account are discussed.

Keywords: Smoking, gender differences, meta-analysis.

Smoking continues to be the leading cause of preventable morbidity and mortality in the United States (USDHHS, 2004). The Center for Disease Control (CDC) reported that nearly a quarter of Americans (22.5%) smoked in 2002 (CDC, 2004). Although a higher percentage of males (25.2%) than females (20.0%) report that they smoke on a daily basis or at least on "some days" (CDC, 2004), 50.9% of men and 46.1% of women who had ever smoked have quit (USDHHS, 2001). The 2001 USDHHS report acknowledges that there is some evidence that women are less successful than men in trying to stop smoking, specifically when gender-related outcomes following nicotine replacement therapies (NRT) are compared. However, the report concludes that the evidence is not convincing. "Since the late 1970s or early 1980s, the probability of attempting to quit smoking and to succeed has been equally high among women and men" (USDHHS, 2001, p. 142). This declaration contradicts an earlier Surgeon General's report that concluded that "women have more difficulty giving up smoking than men" (USDHHS, 1980, p. 307).

Whereas the USDHHS downplays the role of gender in predicting smoking cessation outcome, others disagree. Using comparable birth cohorts, Escobedo and Peddicord (1996) found smoking quit rates among women to be lower than those for men. Research by Fiore et al. (1994) and Wetter et al. (1994) similarly concluded that women seeking treatment for smoking have a more difficult time achieving abstinence than men. Other reviews have also concluded what women are less successful in achieving smoking abstinence and are more likely to relapse than are men (e.g., Blake et al., 1989; Swan, Ward, Jack & Javitz, 1993). Summarizing the effectiveness of NRT among male and female smokers, Perkins (1999) concluded, "... women have slightly or significantly poorer outcome in nearly every clinical outcome study of nicotine replacement that presented outcome separately for men and women... In no study did women have a significantly better outcome than men" (p. 295).

Results from a study by Wetter et al. (1999) illustrate gender-related differences in smoking cessation outcome. Across three randomized, double-blind, placebo-controlled studies on the effectiveness of the nicotine patch involving over 600 participants, Wetter et al.(1999) found that males had higher success rates than women after 1 week of treatment (42% vs. 32%), at the end of treatment involving 8 weeks of counseling (45% vs. 29%), and at 6 months follow-up (25% vs. 12%). Males were more successful than women in achieving smoking abstinence regardless of whether they received an active nicotine patch, a placebo patch, individual counseling, or group counseling. Wetter et al.'s (1999) findings are compatible with other studies tiiat have shown that NRT appears less effective with women than men (Hatsukami, Skcog, Allen, & Bliss, 1995; Kiflen, Fortmann, Newman, & Varady, 1990; Perkins et al., 1996).

Unfortunately, the hypnosis literature has paid relatively little attention to gender in predicting smoking cessation. Green and Lynn's (2000) review of 59 studies that employed hypnosis or suggestion-based interventions for smoking cessation indicated that hypnosis was typically found to be superior to wait-list or no-treatment controls, and many studies found hypnosis to be at least as effective as alternative treatments such as acupuncture, relaxation, and attention placebo. Whereas Green and Lynn concluded that hypnosis was a promising treatment that was possibly efficacious, using criteria set forth by the American Psychological Association's task force on empirically validated treatments (Chambless & Hollen, 1998), they also noted that it was premature to regard hypnosis as a specific and efficacious treatment for smoking cessation. The conclusion was compatible with other reviews (e.g., Abbot Stead, White, & Barnes, 2004) that have urged caution in interpreting the findings in this research area, particularly because many of the studies rely exclusively on self-report and are not randomized controlled trials that permit isolating the specific effects of hypnosis from other interventions.