Revealing the multidimensional framework of the Minnesota Nicotine Withdrawal Scale
The version of the Minnesota Nicotine Withdrawal Scale (MNWS) under consideration consists of nine items. No psychometric analyses of this version have been published. The objectives of this investigation were to perform a factor analysis and to further assess the psychometric properties of the MNWS.
Data came from three Phase II clinical trials on varenicline, developed for smoking cessation, in a sample of smokers. Exploratory factor analysis was used to examine the structure of the MNWS in the first completed study (n = 626) over various time periods. The postulated factor structure was then tested in a set of confirmatory analyses conducted on two subsequent studies (n = 627, n = 312). The proposed structure was further evaluated through construct validity and reliability analyses.
The nine items of the MNWS included the following: urge to smoke (craving); depressed mood; irritability, frustration, or anger; anxiety; difficulty concentrating; restlessness; increased appetite; difficulty going to sleep; and difficulty staying asleep. Each item was rated by a subject on an ordinal scale from 0 (not at all) to 4 (extreme).
Scree plots and rotated factor patterns from the exploratory factor analyses revealed two multi-item domains--Negative Affect with four items and Insomnia with two items--and three individual items (Craving, Restlessness, Increased Appetite). Confirmatory factor analyses supported the structure with fit indexes exceeding 0.90. The multidimensional framework of the MNWS correlated as expected with health status, depicted an expected course of withdrawal symptoms over time, predicted the sensitivity of withdrawal symptoms on subsequent cessation, and produced internal reliability estimates above 0.70.
Evidence is obtained to support the validity and reliability of the multidimensional structure of the nine-item MNWS. The data suggest that the MNWS has individual constructs on Negative Affect (depressed mood; irritability, frustration, or anger; anxiety; difficulty concentrating), Insomnia (difficulty going to sleep; difficulty staying asleep), Craving, Restlessness, and Increased Appetite. As such, analyzing each construct separately would strengthen the analysis of the popular MNWS.
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- "Withdrawal symptoms will be measured 14 times by using the MNWS (item scores 0=“none” to 4=“severe”), reflecting craving for cigarettes, anger, irritability, frustration, anxiety, nervousness, depression, difficulty concentrating, insomnia, restlessness, and increased appetite or weight gain . The MNWS will be collected at screening, weeks 12–15, weeks 26–29, and weeks 49–52. "
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A potential new treatment in smoking cessation and relapse prevention is nicotine vaccination which is based on active immunization against the nicotine molecule. This immunization will elicit the immune system to produce nicotine-specific antibodies that sequester nicotine in the blood stream, after inhaling tobacco products. The resulting antibody-antigen is too large to cross the blood–brain barrier and is therefore postulated to attenuate the rewarding effect of nicotine by preventing the latter from reaching its receptors in the brain and causing the release of dopamine. The aim of this paper is to describe the design of a phase IIb, multi-center, double blind, randomized, placebo controlled trial to assess the efficacy of the nicotine vaccine NicVAX® co-administered with varenicline (Champix®) and intensive counseling as an aid in smoking cessation and relapse prevention.
Two centers will include a total of 600 smokers who are motivated to quit smoking. At week −2 these smokers will be randomized, in a 1:1 ratio, to either 6 injections of NicVAX® or placebo, both co-administered with 12-weeks of varenicline treatment, starting at week 0. The target quit day will be set after 7 days of varenicline treatment at week 1. Smokers will be followed up for 54 weeks. The primary outcome is defined as biochemically validated prolonged smoking abstinence from week 9 to 52. Secondary outcomes include safety, immunogenicity, smoking abstinence from week 37 to 52, abstinence from week 9 to 24, abstinence in the subset of subjects with the highest antibody response, and lapse/relapse rate.
This is the first study to assess the efficacy of a nicotine conjugate vaccine in combination with an evidence-based smoking cessation pharmacotherapy (varenicline) to quit smoking. Although NicVAX® is primarily designed as an aid to smoking cessation, our study is designed to explore its potential to maintain abstinence and prevent relapse. The results of this trial will give a unique insight in the potential of nicotine vaccination for relapse prevention.
Available from: Shahrdad Lotfipour
- "Smokers were considered dependent if they smoked X10 cigarettes/day, had a Fagerström Test for nicotine dependence score X4, a Motivation for Smoking Scale (overall dependence score) X6, and a Shiffman–Jarvik Withdrawal Scale X3 per item. Participants also completed the State-Trait Anxiety Inventory (Spielberger, 1983), as well as the MNWS (Cappelleri et al, 2005; Hughes, 2007a; Hughes et al, 1991; Hughes and Hatsukami, 1986), QSU-brief (Cox et al, 2001), and SUTS (Strength of Urge to Smoke Scale) (Hughes, 2007a; Jarvik et al, 2000). The STAI, MNWS, QSU-brief, and the SUTS were subsequently administered at the five time points defined above, T1–T5, during each of the PET scanning sessions, to monitor craving and withdrawal symptoms during scanning. "
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ABSTRACT: The primary objective of this project was to determine the α4β2(*) nicotinic acetylcholine receptor (nAChR) occupancy in human brain of a single low dose of varenicline (0.5 mg), and to explore the relationship between receptor occupancy by varenicline and tobacco withdrawal symptoms ((*)denoting other putative nAChR subunits). Otherwise healthy smokers (n=9) underwent two positron emission tomography (PET) sessions with the selective α4β2(*) radioligand 2-FA. For the PET sessions, participants received either a low dose of varenicline (0.5 mg) or matching placebo pill (double-blind, random order) before imaging. For both sessions, participants received bolus plus continuous infusions of 2-FA, were scanned for 1 h after allowing the radiotracer to reach a steady state, smoked to satiety, and were scanned for 2 more hours. We estimated the fractional receptor occupancy by a single dose of varenicline (0.5 mg) and the corresponding varenicline dissociation constant (K(V)), along with the effect of low-dose varenicline, pill placebo, and smoking-to-satiety on withdrawal rating scales. The data are compatible with 100% occupancy of α4β2(*) nAChRs by a single dose of varenicline, with a 90% lower confidence limit of 89% occupancy for the thalamus and brainstem. The corresponding 90% upper limit on effective K(V) with respect to plasma varenicline was 0.49 nM. Smoking to satiety, but not low-dose varenicline, significantly reduced withdrawal symptoms. Our findings demonstrate that low-dose varenicline results in saturation of α4β2(*) nAChRs in the thalamus and brainstem without reducing withdrawal symptoms.
Available from: Bradley N Collins
- "" Recent estimates of internal reliability were above .70 (Cappelleri et al., 2005). Because measures of nicotine withdrawal typically correlate strongly with measures of urge and negative affect, for the purpose of this study, we examined other withdrawal-related symptoms grouped in terms of " other physical symptoms " (e.g., sweating, dizziness, tremors, nausea, headache), " energy " (e.g., drowsiness, fatigue), and " hunger " . "
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ABSTRACT: Designing and implementing cue exposure procedures to treat nicotine dependence remains a challenge. This study tested the hypothesis that gender and negative affect (NA) influence changes in smoking urge over time using data from a pilot project testing the feasibility of massed extinction procedures. Forty-three smokers and ex-smokers completed the behavioral laboratory procedures. All participants were over 17 years old, smoked at least 10 cigarettes daily over the last year (or the year prior to quitting) and had expired CO below 10 ppm at the beginning of the ~4-hour session. After informed consent, participants completed 45 min of baseline assessments, and then completed a series of 12 identical, 5-minute exposure trials with inter-trial breaks. Smoking cues included visual, tactile, and olfactory cues with a lit cigarette, in addition to smoking-related motor behaviors without smoking. After each trial, participants reported urge and negative affect (NA). Logistic growth curve models supported the hypothesis that across trials, participants would demonstrate an initial linear increase followed by a decrease in smoking urge (quadratic effect). Data supported hypothesized gender, NA, and gender×NA effects. Significant linear increases in urge were observed among high and low NA males, but not among females in either NA subgroup. A differential quadratic effect showed a significant decrease in urge for the low NA subgroup, but a non-significant decrease in urge in the high NA group. This is the first study to demonstrate gender differences and the effects of NA on the extinction process using a smoking cue exposure paradigm. Results could guide future cue reactivity research and exposure interventions for nicotine dependence.
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