Can the blind see? Participant guess about treatment arm assignment may influence outcome in a clinical trial of bupropion for smoking cessation

Seeing Through the Blind: Belief About Treatment Randomization and Smoking Cessation Outcome Among People With Current or Past Major Depressive Disorder Who Smoke in a Placebo-Controlled Trial of Varenicline

INTRODUCTION

Blinding participants to randomization is a cornerstone of science. However, participant beliefs about their allocation can influence outcomes. We examined blind integrity, the association between trial arm belief and cessation, and potential mechanisms linking treatment arm and treatment arm belief among people with major depressive disorder (MDD) who smoke receiving varenicline in a placebo-controlled trial.

AIMS AND METHODS

175 participants were asked at the end of treatment (EOT) if they thought they received placebo, varenicline, or were not sure. We assessed the relationship between treatment arm belief and actual treatment allocation, examined the association between treatment arm belief and EOT cessation, and evaluated changes in craving, withdrawal, side effects, depression symptoms, and smoking reward as mediators through which treatment arm was believed.

RESULTS

Treatment arm belief was significantly associated with actual arm assignment (χ2(2) = 13.0, p = .002). Participants in the varenicline arm were >3 times as likely to believe they were taking varenicline, versus "not sure" (RR = 3.05 [1.41-6.60], p = .005). Participants in the placebo arm were just as likely to believe they were taking placebo versus "not sure" (χ2[2] = 0.75, p = .69). Controlling for treatment arm, belief that one received varenicline was significantly associated with an increase in cessation rate (OR = 5.91 [2.06-16.92], p = .001). Change in the rewarding experience of smoking may mediate participant ability to discern getting varenicline (B = 0.077 [0.002-0.192], p < .05).

CONCLUSIONS

Participants receiving varenicline can discern that they received varenicline and this belief is associated with higher cessation rates. Research is needed to continue to examine how participants correctly identify their allocation to varenicline.

TRIAL REGISTRATION

Data come from the trial NCT02378714.

IMPLICATIONS

The present study adds to the sparse literature on blind integrity, particularly in the field of tobacco cessation. Randomized clinical trial participants can discern their assignment to varenicline, and believing that one received varenicline was associated with significantly higher cessation rates. Identifying treatment arm allocation may be associated with changes in the rewarding aspects of smoking that have been well documented with varenicline use. Masking allocation to varenicline is challenging. The effects of this medication in clinical trials may represent both pharmacological effects and participants' abilities to recognize that they are receiving the medication.

Distinguishing Immunologic and Behavioral Effects of Vaccination

The interpretation of vaccine efficacy estimands is subtle, even in randomized trials designed to quantify the immunologic effects of vaccination. In this article, we introduce terminology to distinguish between different vaccine efficacy estimands and clarify their interpretations. This allows us to explicitly consider the immunologic and behavioral effects of vaccination, and establish that policy-relevant estimands can differ substantially from those commonly reported in vaccine trials. We further show that a conventional vaccine trial allows the identification and estimation of different vaccine estimands under plausible conditions if one additional post-treatment variable is measured. Specifically, we utilize a "belief variable" that indicates the treatment an individual believed they had received. The belief variable is similar to "blinding assessment" variables that are occasionally collected in placebo-controlled trials in other fields. We illustrate the relations between the different estimands, and their practical relevance, in numerical examples based on an influenza vaccine trial.

Changes in daily dose in open-label compared to double-blind: The role of clients' expectations in injectable opioid agonist treatment

Introduction

Though double-blind studies have indicated that hydromorphone and diacetylmorphine produce similar effects when administered through injectable opioid agonist treatment (iOAT) programs, participant preference may influence some aspects of medication dispensation such as dose.

Methods

 This is a retrospective longitudinal analysis. Participants (n = 131) were previously enrolled in a double-blind clinical trial for iOAT who continued to receive treatment in an open-label follow up study. Data included medication dispensation records from 2012 to 2020. Using linear regression and paired t-tests, average daily dose totals of hydromorphone and diacetylmorphine were examined comparatively between double-blind and open-label periods. A subgroup analysis explored dose difference by preference using the proxy, blinding guess, a variable used to facilitate the measurement of treatment masking during the clinical trial by asking which medication the participant thought they received.

Results

During the open-label period, participants prescribed diacetylmorphine received 49.5 mg less than during the double-blind period (95% CI -12.6,-86.4). Participants receiving hydromorphone did not see a significant dose decrease. Participants who guessed they received hydromorphone during the clinical trial, but learned they were on diacetylmorphine during the open-label period, saw a decrease in total daily dose of 78.3 mg less (95% CI -134.3,-22.4) during the open-label period.

Conclusion

If client preference is considered in the treatment of chronic opioid use disorder, clients may be able to better moderate their dose to suit their individual needs. Together with their healthcare providers, clients can participate in their treatment trajectories collaboratively to optimize client outcomes and promote person-centered treatment options.

Antidepressants for smoking cessation

BACKGROUND

The pharmacological profiles and mechanisms of antidepressants are varied. However, there are common reasons why they might help people to stop smoking tobacco: nicotine withdrawal can produce short-term low mood that antidepressants may relieve; and some antidepressants may have a specific effect on neural pathways or receptors that underlie nicotine addiction.

OBJECTIVES

To assess the evidence for the efficacy, harms, and tolerability of medications with antidepressant properties in assisting long-term tobacco smoking cessation in people who smoke cigarettes.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialised Register, most recently on 29 April 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in people who smoked, comparing antidepressant medications with placebo or no pharmacological treatment, an alternative pharmacotherapy, or the same medication used differently. We excluded trials with fewer than six months of follow-up from efficacy analyses. We included trials with any follow-up length for our analyses of harms.

DATA COLLECTION AND ANALYSIS

We extracted data and assessed risk of bias using standard Cochrane methods. Our primary outcome measure was smoking cessation after at least six months' follow-up. We used the most rigorous definition of abstinence available in each trial, and biochemically validated rates if available. Our secondary outcomes were harms and tolerance outcomes, including adverse events (AEs), serious adverse events (SAEs), psychiatric AEs, seizures, overdoses, suicide attempts, death by suicide, all-cause mortality, and trial dropouts due to treatment. We carried out meta-analyses where appropriate.

MAIN RESULTS

We included a total of 124 studies (48,832 participants) in this review, with 10 new studies added to this update version. Most studies recruited adults from the community or from smoking cessation clinics; four studies focused on adolescents (with participants between 12 and 21 years old). We judged 34 studies to be at high risk of bias; however, restricting analyses only to studies at low or unclear risk of bias did not change clinical interpretation of the results.  There was high-certainty evidence that bupropion increased smoking cessation rates when compared to placebo or no pharmacological treatment (RR 1.60, 95% CI 1.49 to 1.72; I2 = 16%; 50 studies, 18,577 participants). There was moderate-certainty evidence that a combination of bupropion and varenicline may have resulted in superior quit rates to varenicline alone (RR 1.21, 95% CI 0.95 to 1.55; I2 = 15%; 3 studies, 1057 participants). However, there was insufficient evidence to establish whether a combination of bupropion and nicotine replacement therapy (NRT) resulted in superior quit rates to NRT alone (RR 1.17, 95% CI 0.95 to 1.44; I2 = 43%; 15 studies, 4117 participants; low-certainty evidence). There was moderate-certainty evidence that participants taking bupropion were more likely to report SAEs than those taking placebo or no pharmacological treatment. However, results were imprecise and the CI also encompassed no difference (RR 1.16, 95% CI 0.90 to 1.48; I2 = 0%; 23 studies, 10,958 participants). Results were also imprecise when comparing SAEs between people randomised to a combination of bupropion and NRT versus NRT alone (RR 1.52, 95% CI 0.26 to 8.89; I2 = 0%; 4 studies, 657 participants) and randomised to bupropion plus varenicline versus varenicline alone (RR 1.23, 95% CI 0.63 to 2.42; I2 = 0%; 5 studies, 1268 participants). In both cases, we judged evidence to be of low certainty. There was high-certainty evidence that bupropion resulted in more trial dropouts due to AEs than placebo or no pharmacological treatment (RR 1.44, 95% CI 1.27 to 1.65; I2 = 2%; 25 studies, 12,346 participants). However, there was insufficient evidence that bupropion combined with NRT versus NRT alone (RR 1.67, 95% CI 0.95 to 2.92; I2 = 0%; 3 studies, 737 participants) or bupropion combined with varenicline versus varenicline alone (RR 0.80, 95% CI 0.45 to 1.45; I2 = 0%; 4 studies, 1230 participants) had an impact on the number of dropouts due to treatment. In both cases, imprecision was substantial (we judged the evidence to be of low certainty for both comparisons). Bupropion resulted in inferior smoking cessation rates to varenicline (RR 0.73, 95% CI 0.67 to 0.80; I2 = 0%; 9 studies, 7564 participants), and to combination NRT (RR 0.74, 95% CI 0.55 to 0.98; I2 = 0%; 2 studies; 720 participants). However, there was no clear evidence of a difference in efficacy between bupropion and single-form NRT (RR 1.03, 95% CI 0.93 to 1.13; I2 = 0%; 10 studies, 7613 participants). We also found evidence that nortriptyline aided smoking cessation when compared with placebo (RR 2.03, 95% CI 1.48 to 2.78; I2 = 16%; 6 studies, 975 participants), and some evidence that bupropion resulted in superior quit rates to nortriptyline (RR 1.30, 95% CI 0.93 to 1.82; I2 = 0%; 3 studies, 417 participants), although this result was subject to imprecision. Findings were sparse and inconsistent as to whether antidepressants, primarily bupropion and nortriptyline, had a particular benefit for people with current or previous depression.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that bupropion can aid long-term smoking cessation. However, bupropion may increase SAEs (moderate-certainty evidence when compared to placebo/no pharmacological treatment). There is high-certainty evidence that people taking bupropion are more likely to discontinue treatment compared with people receiving placebo or no pharmacological treatment. Nortriptyline also appears to have a beneficial effect on smoking quit rates relative to placebo, although bupropion may be more effective. Evidence also suggests that bupropion may be as successful as single-form NRT in helping people to quit smoking, but less effective than combination NRT and varenicline. In most cases, a paucity of data made it difficult to draw conclusions regarding harms and tolerability. Further studies investigating the efficacy of bupropion versus placebo are unlikely to change our interpretation of the effect, providing no clear justification for pursuing bupropion for smoking cessation over other licensed smoking cessation treatments; namely, NRT and varenicline. However, it is important that future studies of antidepressants for smoking cessation measure and report on harms and tolerability.

Pharmacological Blockade of Muscle Afferents and Perception of Effort: A Systematic Review with Meta-analysis

BACKGROUND

The perception of effort provides information on task difficulty and influences physical exercise regulation and human behavior. This perception differs from other-exercise related perceptions such as pain. There is no consensus on the role of group III/IV muscle afferents as a signal processed by the brain to generate the perception of effort.

OBJECTIVE

The aim of this meta-analysis was to investigate the effect of pharmacologically blocking muscle afferents on the perception of effort.

METHODS

Six databases were searched to identify studies measuring the ratings of perceived effort during physical exercise, with and without pharmacological blockade of muscle afferents. Articles were coded based on the operational measurement used to distinguish studies in which perception of effort was assessed specifically (effort dissociated) or as a composite experience including other exercise-related perceptions (effort not dissociated). Articles that did not provide enough information for coding were assigned to the unclear group.

RESULTS

The effort dissociated group (n = 6) demonstrated a slight increase in ratings of perceived effort with reduced muscle afferent feedback (standard mean change raw, 0.39; 95% confidence interval 0.13-0.64). The group effort not dissociated (n = 2) did not reveal conclusive results (standard mean change raw, - 0.29; 95% confidence interval - 2.39 to 1.8). The group unclear (n = 8) revealed a slight ratings of perceived effort decrease with reduced muscle afferent feedback (standard mean change raw, - 0.27; 95% confidence interval - 0.50 to - 0.04).

CONCLUSIONS

The heterogeneity in results between groups reveals that the inclusion of perceptions other than effort in its rating influences the ratings of perceived effort reported by the participants. The absence of decreased ratings of perceived effort in the effort dissociated group suggests that muscle afferent feedback is not a sensory signal for the perception of effort.

Assessment of patient perception of treatment assignment and patient-reported outcomes in a cannabis use disorder trial

Background: Blinding is a cornerstone of trial methodology. Prior work indicates participant-perceived assignment may be associated with trial outcomes. Less is known about how perception changes over time and if this is associated with outcomes.Objectives: To evaluate if participants change their perception of assignment over time in a blinded trial, and if perception is associated with different types of patient-reported outcomes (PROs).Methods: This was a secondary analysis of data from the Achieving Cannabis Cessation-Evaluating N-Acetylcysteine Treatment (ACCENT) trial, which evaluated the efficacy of N-acetylcysteine (NAC) relative to placebo for treating cannabis use disorder. Participants (N = 234; 164 men, 70 women) were asked at weeks 5 and 9 what treatment (placebo or NAC) they believed they were receiving. We included PROs proximal (cannabis-associated problems, craving) and distal (anxiety) to the intervention. Analysis was by multiple linear regression and mixed models.Results: Approximately 20% of participants in both arms changed their perception over time. Relative to participants who consistently perceived assignment to placebo, participants who consistently perceived assignment to NAC did not always have comparatively better average scores (coefficient -3.3 [95% CI: -7.0, 0.5]). In some analyses, participants who switched to guessing NAC from placebo had comparatively better average scores (coefficient -3.0 [95% CI: -9.3, 3.4]), but this was inconsistent across outcomes or strata defined by actual assignment or guess accuracy.Conclusion: The study suggests that the proportion of individuals who switch their perception over time is modest. However, this group may influence the estimates of intervention effects on some PROs.

Non-pharmacological Considerations in Human Research of Nicotine and Tobacco Effects: A Review

Human research of nicotine and tobacco effects demonstrates that non-pharmacological factors may systematically affect responses to administered substances and inert placebos. Failure to measure or manipulate these factors may compromise study reliability and validity. This is especially relevant for double-blind placebo-controlled research of nicotine, tobacco, and related substances. In this article, we review laboratory-based human research of the impact of non-pharmacological factors on responses to tobacco and nicotine administration. Results suggest that varying beliefs about drug content and effects, perceptions about drug use opportunities, and intentions to cease drug use systematically alter subjective, behavioral, and physiological responses to nicotine, tobacco, and placebo administration. These non-pharmacological factors should be considered when designing and interpreting the findings of human research of nicotine and tobacco effects, particularly when a double-blind placebo-controlled design is used. The clinical implications of these findings are discussed, and we propose methodological strategies to enhance the reliability and validity of future research.

IMPLICATIONS

Growing research demonstrates that non-pharmacological factors systematically alter responses to acute nicotine, tobacco, and placebo administration. Indeed, varying beliefs about nicotine and/or tobacco administration and effects, differing perceptions about nicotine and/or tobacco use opportunities, and inconsistent motivation to quit smoking have been found to exert important influences on subjective, physiological, and behavioral responses. These variables are infrequently measured or manipulated in nicotine and tobacco research, which compromises the validity of study findings. Incorporating methodological strategies to better account for these non-pharmacological factors has the potential to improve the quality of addiction research and treatment.

Antidepressants for smoking cessation

BACKGROUND

Whilst the pharmacological profiles and mechanisms of antidepressants are varied, there are common reasons why they might help people to stop smoking tobacco. Firstly, nicotine withdrawal may produce depressive symptoms and antidepressants may relieve these. Additionally, some antidepressants may have a specific effect on neural pathways or receptors that underlie nicotine addiction.

OBJECTIVES

To assess the evidence for the efficacy, safety and tolerability of medications with antidepressant properties in assisting long-term tobacco smoking cessation in people who smoke cigarettes.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Specialized Register, which includes reports of trials indexed in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO, clinicaltrials.gov, the ICTRP, and other reviews and meeting abstracts, in May 2019.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that recruited smokers, and compared antidepressant medications with placebo or no treatment, an alternative pharmacotherapy, or the same medication used in a different way. We excluded trials with less than six months follow-up from efficacy analyses. We included trials with any follow-up length in safety analyses.

DATA COLLECTION AND ANALYSIS

We extracted data and assessed risk of bias using standard Cochrane methods. We also used GRADE to assess the certainty of the evidence. The primary outcome measure was smoking cessation after at least six months follow-up, expressed as a risk ratio (RR) and 95% confidence intervals (CIs). We used the most rigorous definition of abstinence available in each trial, and biochemically validated rates if available. Where appropriate, we performed meta-analysis using a fixed-effect model. Similarly, we presented incidence of safety and tolerance outcomes, including adverse events (AEs), serious adverse events (SAEs), psychiatric AEs, seizures, overdoses, suicide attempts, death by suicide, all-cause mortality, and trial dropout due to drug, as RRs (95% CIs).

MAIN RESULTS

We included 115 studies (33 new to this update) in this review; most recruited adult participants from the community or from smoking cessation clinics. We judged 28 of the studies to be at high risk of bias; however, restricting analyses only to studies at low or unclear risk did not change clinical interpretation of the results. There was high-certainty evidence that bupropion increased long-term smoking cessation rates (RR 1.64, 95% CI 1.52 to 1.77; I² = 15%; 45 studies, 17,866 participants). There was insufficient evidence to establish whether participants taking bupropion were more likely to report SAEs compared to those taking placebo. Results were imprecise and CIs encompassed no difference (RR 1.16, 95% CI 0.90 to 1.48; I² = 0%; 21 studies, 10,625 participants; moderate-certainty evidence, downgraded one level due to imprecision). We found high-certainty evidence that use of bupropion resulted in more trial dropouts due to adverse events of the drug than placebo (RR 1.37, 95% CI 1.21 to 1.56; I² = 19%; 25 studies, 12,340 participants). Participants randomized to bupropion were also more likely to report psychiatric AEs compared with those randomized to placebo (RR 1.25, 95% CI 1.15 to 1.37; I² = 15%; 6 studies, 4439 participants). We also looked at the safety and efficacy of bupropion when combined with other non-antidepressant smoking cessation therapies. There was insufficient evidence to establish whether combination bupropion and nicotine replacement therapy (NRT) resulted in superior quit rates to NRT alone (RR 1.19, 95% CI 0.94 to 1.51; I² = 52%; 12 studies, 3487 participants), or whether combination bupropion and varenicline resulted in superior quit rates to varenicline alone (RR 1.21, 95% CI 0.95 to 1.55; I² = 15%; 3 studies, 1057 participants). We judged the certainty of evidence to be low and moderate, respectively; in both cases due to imprecision, and also due to inconsistency in the former. Safety data were sparse for these comparisons, making it difficult to draw clear conclusions. A meta-analysis of six studies provided evidence that bupropion resulted in inferior smoking cessation rates to varenicline (RR 0.71, 95% CI 0.64 to 0.79; I² = 0%; 6 studies, 6286 participants), whilst there was no evidence of a difference in efficacy between bupropion and NRT (RR 0.99, 95% CI 0.91 to 1.09; I² = 18%; 10 studies, 8230 participants). We also found some evidence that nortriptyline aided smoking cessation when compared with placebo (RR 2.03, 95% CI 1.48 to 2.78; I² = 16%; 6 studies, 975 participants), whilst there was insufficient evidence to determine whether bupropion or nortriptyline were more effective when compared with one another (RR 1.30 (favouring bupropion), 95% CI 0.93 to 1.82; I² = 0%; 3 studies, 417 participants). There was no evidence that any of the other antidepressants tested (including St John's Wort, selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs)) had a beneficial effect on smoking cessation. Findings were sparse and inconsistent as to whether antidepressants, primarily bupropion and nortriptyline, had a particular benefit for people with current or previous depression.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that bupropion can aid long-term smoking cessation. However, bupropion also increases the number of adverse events, including psychiatric AEs, and there is high-certainty evidence that people taking bupropion are more likely to discontinue treatment compared with placebo. However, there is no clear evidence to suggest whether people taking bupropion experience more or fewer SAEs than those taking placebo (moderate certainty). Nortriptyline also appears to have a beneficial effect on smoking quit rates relative to placebo. Evidence suggests that bupropion may be as successful as NRT and nortriptyline in helping people to quit smoking, but that it is less effective than varenicline. There is insufficient evidence to determine whether the other antidepressants tested, such as SSRIs, aid smoking cessation, and when looking at safety and tolerance outcomes, in most cases, paucity of data made it difficult to draw conclusions. Due to the high-certainty evidence, further studies investigating the efficacy of bupropion versus placebo are unlikely to change our interpretation of the effect, providing no clear justification for pursuing bupropion for smoking cessation over front-line smoking cessation aids already available. However, it is important that where studies of antidepressants for smoking cessation are carried out they measure and report safety and tolerability clearly.

Long-term nicotine replacement therapy: a randomized clinical trial

IMPORTANCE

The US Food and Drug Administration adopted labeling for nicotine patches to allow use beyond the standard 8 weeks. This decision was based in part on data showing increased efficacy for 24 weeks of treatment. Few studies have examined whether the use of nicotine patches beyond 24 weeks provides additional therapeutic benefit.

OBJECTIVE

To compare 8 (standard), 24 (extended), and 52 (maintenance) weeks of nicotine patch treatment for promoting tobacco abstinence.

DESIGN, SETTING, AND PARTICIPANTS

We recruited 525 treatment-seeking smokers for a randomized clinical trial conducted from June 22, 2009, through April 15, 2014, through 2 universities.

INTERVENTIONS

Smokers received 12 smoking cessation behavioral counseling sessions and were randomized to 8, 24, or 52 weeks of nicotine patch treatment.

MAIN OUTCOMES AND MEASURES

The primary outcome was 7-day point prevalence abstinence, confirmed with breath levels of carbon monoxide at 6 and 12 months (intention to treat).

RESULTS

At 24 weeks, 21.7% of participants in the standard treatment arm were abstinent, compared with 27.2% of participants in the extended and maintenance treatment arms (χ(2)(1) = 1.98; P = .17). In a multivariate model controlled for covariates, participants in the extended and maintenance treatment arms reported significantly greater abstinence rates at 24 weeks compared with participants in the standard treatment arm (odds ratio [OR], 1.70 [95% CI, 1.03-2.81]; P = .04), had a longer duration of abstinence until relapse (β = 21.30 [95% CI, 10.30-32.25]; P < .001), reported smoking fewer cigarettes per day if not abstinent (mean [SD], 5.8 [5.3] vs 6.4 [5.1] cigarettes per day; β = 0.43 [95% CI, 0.06-0.82]; P = .02), and reported more abstinent days (mean [SD], 80.5 [38.1] vs 68.2 [43.7] days; OR, 1.55 [95% CI, 1.06-2.26]; P = .02). At 52 weeks, participants in the maintenance treatment arm did not report significantly greater abstinence rates compared with participants in the standard and extended treatment arms (20.3% vs 23.8%; OR, 1.17 [95% CI, 0.69-1.98]; P = .57). Similarly, we found no difference in week 52 abstinence rates between participants in the extended and standard treatment arms (26.0% vs 21.7%; OR, 1.33 [95% CI, 0.72-2.45]; P = .36). Treatment duration was not associated with any adverse effects or adherence to the counseling regimen, but participants in the maintenance treatment arm reported lower adherence to the nicotine patch regimen compared with those in the standard and extended treatment arms (mean [SD], 3.94 [2.5], 4.61 [2.0], and 4.7 [2.4] patches/wk, respectively; F2,522 = 6.03; P = .003).

CONCLUSIONS AND RELEVANCE

The findings support the safety of long-term use of nicotine patch treatment, although they do not support efficacy beyond 24 weeks of treatment in a broad group of smokers.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01047527.

Association between physician beliefs regarding assigned treatment and clinical response: re-analysis of data from the Hypericum Depression Trial Study Group

BACKGROUND

We have previously shown an association between patient belief and treatment response in the Hypericum Depression Trial Study Group's 2002 study. We re-examined these data to determine whether clinical improvement was associated with physician belief about assigned therapy.

METHODS

Three hundred and forty adults with major depression and baseline scores ≥20 on the 17-item Hamilton Depression Scale (HDRS-17) were randomized to Hypericum 900-1500mg/day, sertraline 50-100mg/day, or placebo for 8 weeks. At week 8, physicians guessed their patients' treatment. We analyzed 277 subjects with at least one post-baseline visit and physician guess data. We examined association between guess and improvement in HDRS-17 and whether treatment assignment moderated the effect of belief on remission (final HDRS-17 score <8).

RESULTS

Patient and doctor guesses agreed at 53% for sertraline, 68% for Hypericum, and 52% for placebo (kappa=0.37). Doctors guessed placebo correctly (38%) more than sertraline (18%) or Hypericum (19%) (p=0.001). Adverse event scores were significantly greater among subjects for which the clinicians guessed Hypericum (p<0.001) or sertraline (p=0.005) compared to placebo. Significant improvements in HDRS-17 score were found when comparing the Hypericum-guess (p<0.001) or the sertraline-guess group (p<0.001) against the placebo-guess group. Remission rates were significantly greater for subjects whose clinicians guessed sertraline (p<0.001) or Hypericum (p<0.001) versus placebo.

CONCLUSION

Doctors tended to guess placebo more easily than Hypericum or sertraline, and their guesses tended to favor active therapies when improvement was more robust. Results show association but not causation, and merit more careful investigation.

Smokers' Treatment Expectancies Predict Smoking Cessation Success

INTRODUCTION

Smokers' treatment expectancies may influence their choice of a particular medication as well as their medication experience.

AIMS

This study examined the role of smokers' treatment expectancies to their smoking cessation outcomes in a completed, randomized, placebo-controlled trial of naltrexone for smoking cessation, controlling for perceptions of treatment assignment.

METHODS

Treatment seeking cigarette smokers (N = 315) were randomized to receive either naltrexone (50 mg) or placebo in combination with nicotine patch and behavioral counseling. Expectancies for naltrexone as a smoking cessation aid were assessed at baseline and 4 weeks after the quit date.

RESULTS

More positive baseline medication expectancies predicted higher quit rates at one month in the naltrexone (OR =1.45, p =.04) group but were associated with lower quit rates in the placebo group (OR =.66, p =.03). Maintaining and/or increasing positive medication expectancies in the first month of treatment was associated with better pill adherence during this interval in the naltrexone group (ps <.05). Positive baseline medication expectancies were also associated with the perception of having received naltrexone over placebo among all participants.

CONCLUSIONS

Positive medication expectancies in smokers may contribute to better treatment response. Assessing treatment expectancies and attempting to maintain or improve them may be important for the delivery, evaluation, and targeting of smoking cessation treatments.

Perceived medication assignment during a placebo-controlled laboratory study of varenicline: temporal associations of treatment expectancies with smoking-related outcomes

RATIONALE

Expectancies regarding treatment assignment may influence outcomes in placebo-controlled trials above and beyond actual treatment assignment. For smoking pharmacotherapies, guessing enrollment in the active medication treatment is associated with higher abstinence rates. However, placebo-controlled trials of smoking pharmacotherapies rarely assess perceived treatment assignment and those that do only collect this information after reaching full dosage.

OBJECTIVES

To determine the temporal relationship between treatment expectancies and smoking-related variables, we assessed the impact of treatment guess during a placebo-controlled laboratory study of varenicline on measures of craving, smoking reward, and smoking reinforcement. We hypothesized that treatment guess at mid-titration would influence smoking-related measures at full dosage, above and beyond actual medication effects. We also explored factors related to guess stability and differences in blind fidelity between mid-drug titration and full dosage.

METHODS

Eighty-eight participants completed laboratory assessments at baseline, mid-titration, and full dosage that involved self-report and behavioral measures of tonic craving, cue-provoked craving, smoking reward, and smoking reinforcement. Participants guessed treatment assignment at mid-titration and full dosage.

RESULTS

Generalized linear models confirmed that, beyond actual treatment assignment, treatment guess improved model fit for both self-report and behavioral smoking-related measures. Further, accuracy of treatment guess improved from titration to full dosage, and specific demographic factors (e.g., gender, race) were associated with type of treatment guess and guess stability across time.

CONCLUSIONS

These results reinforce the importance of assessing perceived treatment assignment repeatedly during placebo-controlled trials and suggest that treatment expectancies during titration can affect outcomes once full dosage has been reached.

Antidepressants for smoking cessation

BACKGROUND

There are at least three reasons to believe antidepressants might help in smoking cessation. Firstly, nicotine withdrawal may produce depressive symptoms or precipitate a major depressive episode and antidepressants may relieve these. Secondly, nicotine may have antidepressant effects that maintain smoking, and antidepressants may substitute for this effect. Finally, some antidepressants may have a specific effect on neural pathways (e.g. inhibiting monoamine oxidase) or receptors (e.g. blockade of nicotinic-cholinergic receptors) underlying nicotine addiction.

OBJECTIVES

The aim of this review is to assess the effect and safety of antidepressant medications to aid long-term smoking cessation. The medications include bupropion; doxepin; fluoxetine; imipramine; lazabemide; moclobemide; nortriptyline; paroxetine; S-Adenosyl-L-Methionine (SAMe); selegiline; sertraline; St. John's wort; tryptophan; venlafaxine; and zimeledine.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialised Register which includes reports of trials indexed in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and PsycINFO, and other reviews and meeting abstracts, in July 2013.

SELECTION CRITERIA

We considered randomized trials comparing antidepressant medications to placebo or an alternative pharmacotherapy for smoking cessation. We also included trials comparing different doses, using pharmacotherapy to prevent relapse or re-initiate smoking cessation or to help smokers reduce cigarette consumption. We excluded trials with less than six months follow-up.

DATA COLLECTION AND ANALYSIS

We extracted data and assessed risk of bias using standard methodological procedures expected by the Cochrane Collaboration.The main outcome measure was abstinence from smoking after at least six months follow-up in patients smoking at baseline, expressed as a risk ratio (RR). We used the most rigorous definition of abstinence available in each trial, and biochemically validated rates if available. Where appropriate, we performed meta-analysis using a fixed-effect model.

MAIN RESULTS

Twenty-four new trials were identified since the 2009 update, bringing the total number of included trials to 90. There were 65 trials of bupropion and ten trials of nortriptyline, with the majority at low or unclear risk of bias. There was high quality evidence that, when used as the sole pharmacotherapy, bupropion significantly increased long-term cessation (44 trials, N = 13,728, risk ratio [RR] 1.62, 95% confidence interval [CI] 1.49 to 1.76). There was moderate quality evidence, limited by a relatively small number of trials and participants, that nortriptyline also significantly increased long-term cessation when used as the sole pharmacotherapy (six trials, N = 975, RR 2.03, 95% CI 1.48 to 2.78). There is insufficient evidence that adding bupropion (12 trials, N = 3487, RR 1.9, 95% CI 0.94 to 1.51) or nortriptyline (4 trials, N = 1644, RR 1.21, 95% CI 0.94 to 1.55) to nicotine replacement therapy (NRT) provides an additional long-term benefit. Based on a limited amount of data from direct comparisons, bupropion and nortriptyline appear to be equally effective and of similar efficacy to NRT (bupropion versus nortriptyline 3 trials, N = 417, RR 1.30, 95% CI 0.93 to 1.82; bupropion versus NRT 8 trials, N = 4096, RR 0.96, 95% CI 0.85 to 1.09; no direct comparisons between nortriptyline and NRT). Pooled results from four trials comparing bupropion to varenicline showed significantly lower quitting with bupropion than with varenicline (N = 1810, RR 0.68, 95% CI 0.56 to 0.83). Meta-analyses did not detect a significant increase in the rate of serious adverse events amongst participants taking bupropion, though the confidence interval only narrowly missed statistical significance (33 trials, N = 9631, RR 1.30, 95% CI 1.00 to 1.69). There is a risk of about 1 in 1000 of seizures associated with bupropion use. Bupropion has been associated with suicide risk, but whether this is causal is unclear. Nortriptyline has the potential for serious side-effects, but none have been seen in the few small trials for smoking cessation.There was no evidence of a significant effect for selective serotonin reuptake inhibitors on their own (RR 0.93, 95% CI 0.71 to 1.22, N = 1594; 2 trials fluoxetine, 1 paroxetine, 1 sertraline) or as an adjunct to NRT (3 trials of fluoxetine, N = 466, RR 0.70, 95% CI 0.64 to 1.82). Significant effects were also not detected for monoamine oxidase inhibitors (RR 1.29, 95% CI 0.93 to 1.79, N = 827; 1 trial moclobemide, 5 selegiline), the atypical antidepressant venlafaxine (1 trial, N = 147, RR 1.22, 95% CI 0.64 to 2.32), the herbal therapy St John's wort (hypericum) (2 trials, N = 261, RR 0.81, 95% CI 0.26 to 2.53), or the dietary supplement SAMe (1 trial, N = 120, RR 0.70, 95% CI 0.24 to 2.07).

AUTHORS' CONCLUSIONS

The antidepressants bupropion and nortriptyline aid long-term smoking cessation. Adverse events with either medication appear to rarely be serious or lead to stopping medication. Evidence suggests that the mode of action of bupropion and nortriptyline is independent of their antidepressant effect and that they are of similar efficacy to nicotine replacement. Evidence also suggests that bupropion is less effective than varenicline, but further research is needed to confirm this finding. Evidence suggests that neither selective serotonin reuptake inhibitors (e.g. fluoxetine) nor monoamine oxidase inhibitors aid cessation.

Treatment assignment guesses by study participants in a double-blind dose escalation clinical trial of saw palmetto

OBJECTIVES

This report assesses participant perception of treatment assignment in a randomized, double-blind, placebo-controlled trial of saw palmetto for the treatment of benign prostatic hyperplasia (BCM).

DESIGN

Participants randomized to receive saw palmetto were instructed to take one 320 mg gelcap daily for the first 24 weeks, two 320 mg gelcaps daily for the second 24 weeks, and three 320 mg gelcaps daily for the third 24 weeks. Study participants assigned to placebo were instructed to take the same number of matching placebo gelcaps in each time period. At 24, 48, and 72 weeks postrandomization, the American Urological Association Symptom Index (AUA-SI) was administered and participants were asked to guess their treatment assignment.

SETTINGS

The study was conducted at 11 clinical centers in North America.

PARTICIPANTS

Study participants were men, 45 years and older, with moderate to low severe BPH symptoms, randomized to saw palmetto (N=151) or placebo (N=155).

OUTCOME MEASURES

Treatment arms were compared with respect to the distribution of participant guesses of treatment assignment.

RESULTS

For participants assigned to saw palmetto, 22.5%, 24.7%, and 29.8% correctly thought they were taking saw palmetto, and 37.3%, 40.0%, and 44.4% incorrectly thought they were on placebo at 24, 48, and 72 weeks, respectively. For placebo participants, 21.8%, 27.4%, and 25.2% incorrectly thought they were on saw palmetto, and 41.6%, 39.9%, and 42.6% correctly thought they were on placebo at 24, 48, and 72 weeks, respectively. The treatment arms did not vary with respect to the distributions of participants who guessed they were on saw palmetto (p=0.823) or placebo (p=0.893). Participants who experienced an improvement in AUA-SI were 2.16 times more likely to think they were on saw palmetto.

CONCLUSIONS

Blinding of treatment assignment was successful in this study. Improvement in BPH-related symptoms was associated with the perception that participants were taking saw palmetto.

Perceived treatment assignment and smoking cessation in a clinical trial of bupropion versus placebo

INTRODUCTION

Psychoactive effects of smoking cessation medi cations such as bupropion may allow participants in smoking cessation clinical trials to correctly guess their treatment assignment at rates greater than chance. Previous research has found an association between perceived treatment assignment and smoking cessation rates among moderate to heavy smokers (≥ 10 cigarettes per day [cpd]) in two bupropion clinical trials.

METHODS

The aim of this study was to determine the impact of perceived treatment assignment on end-of-treatment cotinine-verified smoking abstinence at Week 7 and Week 26 among African American light smokers (≤ 10 cpd) enrolled in a double-blind, placebo-controlled study of bupropion. Participants (n = 390) included in this study reported their perceived treatment assignment on the end-of-treatment (Week 7) survey.

RESULTS

Participants were predominantly female (63.1%), 48.1 years of age (SD = 11.2), and smoked an average of 8 cpd (SD = 2.5). Participants given bupropion were more likely to correctly guess their treatment assignment (69%; 140/203) than those assigned to placebo (51.3%; 96/187) (p < .0001). After adjusting for treatment condition, participants who perceived assignment to bupropion versus placebo were not more likely to be abstinent than those who perceived assignment to placebo at Week 7 or at Week 26. The interaction between treatment and perceived treatment assignment was also nonsignificant.

CONCLUSIONS

Consistent with two previous studies testing bupropion, participants assigned to bupropion were more likely to correctly guess their treatment assignment than those assigned to placebo. However, in contrast to previous studies with heavier smokers, perceived treatment assignment did not significantly impact cotinine-verified abstinence in light smokers.

Incremental efficacy of adding bupropion to the nicotine patch for smoking cessation in smokers with a recent history of alcohol dependence: results from a randomized, double-blind, placebo-controlled study

AIMS

The primary aim of this study was to compare the efficacy of smoking cessation treatment using a combination of nicotine patch and bupropion vs. nicotine patch and placebo bupropion. A secondary aim was to investigate whether the efficacy of bupropion is moderated by belief about whether one is receiving active or placebo medication.

METHODS

Participants were recruited from a residential substance abuse treatment program and the community. We randomly assigned 148 smokers with between 2 and 12 months of alcohol abstinence to nicotine patch plus bupropion or nicotine patch plus placebo. All participants also received seven counseling sessions.

RESULTS

At follow up, differences between medication conditions were not significant. Seven-day point prevalence quit rates in the patch plus bupropion vs. patch plus placebo conditions at week 24 were 6% and 11%, respectively. Differences between groups on prolonged abstinence and time to first smoking lapse were also not significant. However, among participants who received bupropion, those who accurately "guessed" that they were receiving bupropion were more likely to remain abstinent than those who incorrectly believed they were receiving placebo.

CONCLUSIONS

Findings do not support combining nicotine patch and bupropion for smoking cessation in this population. However, findings support previous studies suggesting the importance of assessing the blind in smoking cessation studies and its possible moderating effect on medication efficacy. Future directions for enhancing smoking cessation outcome in these smokers include investigations of intensive behavioral and pharmacological interventions, including studies of potential interactions between individual genetic differences and medication efficacy.

Perceived drug assignment and treatment outcome in smokers given nicotine patch therapy

This study assessed the relationship between treatment outcome and perceived drug assignment in smokers (nicotine patch [NP] or placebo) using abstinence and relapse status. Smokers (N = 424) were randomly assigned to receive either NP or placebo as part of a study that examined the effects of combining NP with self-help programs. Beliefs about drug assignment, assessed at the 12-month follow-up, were obtained from 384 participants. Beliefs were related to abstinence at the 2-month, p < .05, and 6-month follow-ups, p < .05, for the NP group, but not the placebo. Beliefs were not related to abstinence at 12 months for either group. Survival analysis assessing relapse revealed that beliefs were related to relapse status, regardless of actual group assignment. Our results suggest that there is a relationship between perceived drug assignment and treatment outcome. Future studies using multiple treatment outcome measures and assessments of beliefs over time are warranted.

Psychological mediators of bupropion sustained-release treatment for smoking cessation

AIM

The study aimed to test simultaneously our understanding of the effects of bupropion sustained-release (SR) treatment on putative mediators and our understanding of determinants of post-quit abstinence, including withdrawal distress, cigarette craving, positive affect and subjective reactions to cigarettes smoked during a lapse. The specificity of bupropion SR effects was also tested in exploratory analyses.

DESIGN

Data from a randomized, placebo-controlled clinical trial of bupropion SR were submitted to mediation analyses.

SETTING

Center for Tobacco Research and Intervention, Madison, WI, USA.

PARTICIPANTS

A total of 403 adult, daily smokers without contraindications to bupropion SR use.

INTERVENTION

Participants were assigned randomly to receive a 9-week course of bupropion SR or placebo pill and to receive eight brief individual counseling sessions or no counseling.

MEASUREMENTS

Ecological momentary assessment ratings of smoking behavior and putative mediators were collected pre- and post-quit.

FINDINGS

Results of structural equation and hierarchical linear models did not support the hypothesis that bupropion SR treatment improves short-term abstinence by reducing withdrawal distress or affecting the subjective effects of a lapse cigarette, but provided partial support for mediation by cigarette craving reduction and enhanced positive affect. Bupropion SR effects on point-prevalence abstinence at 1 month post-quit were also mediated partially by enhanced motivation to quit and self-efficacy.

CONCLUSIONS

Results provided some support for models of bupropion SR treatment and relapse and suggested that motivational processes may partially account for bupropion SR efficacy.

Antidepressants for smoking cessation

BACKGROUND

There are at least two theoretical reasons to believe antidepressants might help in smoking cessation. Nicotine withdrawal may produce depressive symptoms or precipitate a major depressive episode and antidepressants may relieve these. Nicotine may have antidepressant effects that maintain smoking, and antidepressants may substitute for this effect. Alternatively, some antidepressants may have a specific effect on neural pathways underlying nicotine addiction, (e.g. blocking nicotine receptors) independent of their antidepressant effects.

OBJECTIVES

The aim of this review is to assess the effect of antidepressant medications in aiding long-term smoking cessation. The medications include bupropion; doxepin; fluoxetine; imipramine; moclobemide; nortriptyline; paroxetine; sertraline, tryptophan and venlafaxine.

SEARCH STRATEGY

We searched the Cochrane Tobacco Addiction Group trials register which includes trials indexed in MEDLINE, EMBASE, SciSearch and PsycINFO, and other reviews and meeting abstracts, in September 2006.

SELECTION CRITERIA

We considered randomized trials comparing antidepressant medications to placebo or an alternative pharmacotherapy for smoking cessation. We also included trials comparing different doses, using pharmacotherapy to prevent relapse or re-initiate smoking cessation or to help smokers reduce cigarette consumption. We excluded trials with less than six months follow up.

DATA COLLECTION AND ANALYSIS

We extracted data in duplicate on the type of study population, the nature of the pharmacotherapy, the outcome measures, method of randomization, and completeness of follow up. The main outcome measure was abstinence from smoking after at least six months follow up in patients smoking at baseline, expressed as an odds ratio (OR). We used the most rigorous definition of abstinence available in each trial, and biochemically validated rates if available. Where appropriate, we performed meta-analysis using a fixed-effect model.

MAIN RESULTS

Seventeen new trials were identified since the last update in 2004 bringing the total number of included trials to 53. There were 40 trials of bupropion and eight trials of nortriptyline. When used as the sole pharmacotherapy, bupropion (31 trials, odds ratio [OR] 1.94, 95% confidence interval [CI] 1.72 to 2.19) and nortriptyline (four trials, OR 2.34, 95% CI 1.61 to 3.41) both doubled the odds of cessation. There is insufficient evidence that adding bupropion or nortriptyline to nicotine replacement therapy provides an additional long-term benefit. Three trials of extended therapy with bupropion to prevent relapse after initial cessation did not find evidence of a significant long-term benefit. From the available data bupropion and nortriptyline appear to be equally effective and of similar efficacy to nicotine replacement therapy. Pooling three trials comparing bupropion to varenicline showed a lower odds of quitting with bupropion (OR 0.60, 95% CI 0.46 to 0.78). There is a risk of about 1 in 1000 of seizures associated with bupropion use. Concerns that bupropion may increase suicide risk are currently unproven. Nortriptyline has the potential for serious side-effects, but none have been seen in the few small trials for smoking cessation. There were six trials of selective serotonin reuptake inhibitors; four of fluoxetine, one of sertraline and one of paroxetine. None of these detected significant long-term effects, and there was no evidence of a significant benefit when results were pooled. There was one trial of the monoamine oxidase inhibitor moclobemide, and one of the atypical antidepressant venlafaxine. Neither of these detected a significant long-term benefit.

AUTHORS' CONCLUSIONS

The antidepressants bupropion and nortriptyline aid long-term smoking cessation but selective serotonin reuptake inhibitors (e.g. fluoxetine) do not. Evidence suggests that the mode of action of bupropion and nortriptyline is independent of their antidepressant effect and that they are of similar efficacy to nicotine replacement. Adverse events with both medications are rarely serious or lead to stopping medication.