Behavioral tasks sensitive to acute abstinence and predictive of smoking cessation success: A systematic review and meta-analysis

BACKGROUND AND AIMS: Performance on cognitive tasks may be sensitive to acute smoking abstinence and may also predict whether quit attempts fail. Our aim was to conduct a systematic review and meta-analysis to identify cognitive tasks sensitive to acute abstinence and predictive of smoking cessation success. METHODS: Embase, Medline, PsycInfo and Web of Science were searched up to March 2016. Studies were included if they enrolled adults and assessed smoking using used a quantitative measure. Studies were combined in a random effects meta-analysis. RESULTS: We included 42 acute abstinence studies and 13 cessation studies. There was evidence for an effect of abstinence on delay discounting [d = 0.26, 95% CI 0.07 to 0.45, p = 0.005], response inhibition [d = 0.48, 95% CI 0.26 to 0.70, p < 0.001], mental arithmetic [d = 0.38, 95% CI 0.06 to 0.70, p = 0.018], and recognition memory [d = 0.46, 95% CI 0.23 to 0.70, p < 0.001]. In contrast performance on the Stroop [d =0 .17, 95% CI -0.17 to 0.51, p = 0.333] and smoking Stroop [d = 0.03, 95% CI -0.11 to 0.17, p = 0.675] task was not influenced by abstinence. We found only weak evidence for an effect of acute abstinence on dot probe task performance [d = 0.15, 95% CI -0.01 to 0.32, p = 0.072]. The design of the cessation studies was too heterogeneous to permit meta-analysis. CONCLUSIONS: Compared with satiated smokers, acutely abstinent smokers display higher delay discounting, lower response inhibition, impaired arithmetic, and recognition memory performance. However, reaction time measures of cognitive bias appear to be unaffected by acute tobacco abstinence. Conclusions about cognitive tasks that predict smoking cessation success were limited by methodological inconsistencies

Meta-analytical methods to identify who benefits most from treatments: daft, deluded, or deft approach?

Identifying which individuals benefit most from particular treatments or other interventions underpins so-called personalised or stratified medicine. However, single trials are typically underpowered for exploring whether participant characteristics, such as age or disease severity, determine an individual’s response to treatment. A meta-analysis of multiple trials, particularly one where individual participant data (IPD) are available, provides greater power to investigate interactions between participant characteristics (covariates) and treatment effects. We use a published IPD meta-analysis to illustrate three broad approaches used for testing such interactions. Based on another systematic review of recently published IPD meta-analyses, we also show that all three approaches can be applied to aggregate data as well as IPD. We also summarise which methods of analysing and presenting interactions are in current use, and describe their advantages and disadvantages. We recommend that testing for interactions using within-trials information alone (the deft approach) becomes standard practice, alongside graphical presentation that directly visualises this

Additive Effects of 3,4-Methylenedioxymethamphetamine (MDMA) and Compassionate Imagery on Self-Compassion in Recreational Users of Ecstasy

3,4-Methylenedioxymethylamphetamine (MDMA;‘ecstasy’) produces prosocial subjective effects that may extend to affiliative feelings towards the self. Behavioural techniques can produce similar self-directed affiliation. For example, compassionate imagery (CI) and ecstasy reduce self-criticism and increase self-compassion to a similar extent, with the effects of CI enhanced in the presence of ecstasy. Here, we examine self-compassion and self-criticism in recreational users who consumed chemically verified MDMA in a within-subjects crossover study. In a naturalistic setting, polydrug-using participants performed a self-focused CI exercise on two occasions separated by ≥6 days: once having consumed self-sourced MDMA and once not. Effects on state self-criticism, self-compassion and emotional empathy were assessed before and after MDMA use (or over an extended baseline period on the occasion that MDMA was not consumed) and reassessed after CI. In participants (n = 20; 8 women) whose ecstasy contained MDMA and no other drug, CI and MDMA appeared to separately increase emotional empathy (to critical facial expressions) and self-compassion. The effects of CI and MDMA on self-compassion also appeared to be additive. Establishing the observed effects in controlled studies will be critical for determining the combined utility of these approaches in fostering adaptive self-attitudes in a therapeutic context

A comparison of emotion regulation strategies in response to craving cognitions: Effects on smoking behaviour, craving and affect in dependent smokers

AIM: The effects of three emotion regulation strategies that targeted smoking-related thoughts were compared on outcomes relevant to smoking cessation. METHOD: Daily smokers applied defusion (n = 25), reappraisal (n = 25) or suppression (n = 23) to thoughts associated with smoking during a cue-induced craving procedure. Smoking behaviour, approach/avoidance behavioural bias, and subjective measures of experiential avoidance, craving, and affect were assessed during the experimental session, with additional behavioural and subjective outcomes assessed at 24 h and seven day follow-up. The influence of baseline group differences in smoking level and nicotine dependence were explored statistically. RESULTS: Defusion and reappraisal were associated with greater restraint in smoking behaviour in the immediate post-session period as well as reduction in smoking at seven day follow-up compared to suppression. Relative to suppression, reduced subjective craving was seen in the reappraisal group, and reduced experiential avoidance in the defusion group. Differences in approach/avoidance responses to smoking and neutral cues were observed only between the suppression and reappraisal groups. Although suppression was rated as lower in both credibility and strategy-expectancy compared to defusion and reappraisal, neither credibility nor expectancy mediated the effect of any strategy on changes in levels of smoking. CONCLUSION: Defusion and reappraisal produced similar benefits in smoking-related behavioural outcomes but, relative to suppression, were associated with distinctive outcomes on experiential avoidance and craving. The effects appear to be independent of perceived expectancy and credibility of the different strategies. Overall, the results suggest a role for reappraisal and defusion strategies in the development of psychological treatments for addiction-related disorders

The Acute Effects of a Dopamine D3 Receptor Preferring Agonist on Motivation for Cigarettes in Dependent and Occasional Cigarette Smokers

Background: Dopaminergic functioning is thought to play critical roles in both motivation and addiction. There is preliminary evidence that dopamine agonists reduce the motivation for cigarettes in smokers. However, the effects of pramipexole, a dopamine D3 receptor preferring agonist, have not been investigated. The aim of this study was to examine the effects of an acute dose of pramipexole on the motivation to earn cigarettes and nondrug rewards. Methods: Twenty dependent and 20 occasional smokers received 0.5 mg pramipexole using a double-blind, placebo-controlled crossover design. Motivation for cigarettes and consummatory nondrug rewards was measured using the DReaM-Choice task, in which participants earned, and later "consumed," cigarettes, music, and chocolate. Demand for cigarettes was measured using the Cigarette Purchase Task (CPT). Self-reported craving, withdrawal, and drug effects were also recorded. Results: Dependent smokers chose (p < .001) and button-pressed for (p < .001) cigarettes more, and chose chocolate less (p < .001), than occasional smokers. Pramipexole did not affect the number of choices for or amount of button-pressing for any reward including cigarettes, which was supported by a Bayesian analysis. The dependent smokers had greater demand for cigarettes than occasional smokers across all CPT outcomes (ps < .021), apart from elasticity. Pramipexole did not affect demand for cigarettes, and this was supported by Bayesian analyses. Pramipexole produced greater subjective "feel drug" and "dislike drug" effects than placebo. Conclusions: Dependent and occasional cigarette smokers differed in their motivation for cigarettes but not for the nondrug rewards. Pramipexole did not acutely alter motivation for cigarettes. These findings question the role of dopamine D3 receptors in cigarette-seeking behavior in dependent and occasional smokers. Implications: This study adds to the growing literature about cigarette versus nondrug reward processing in nicotine dependence and the role of dopamine in cigarette-seeking behavior. Our results suggest nicotine dependence is associated with a hypersensitivity to cigarette rewards but not a hyposensitivity to nondrug rewards. Furthermore, our results question the importance of dopamine D3 receptors in motivational processing of cigarettes in occasional and dependent smokers

Acute and chronic effects of cannabinoids on effort-related decision-making and reward learning: an evaluation of the cannabis 'amotivational' hypotheses

Rationale: Anecdotally, both acute and chronic cannabis use have been associated with apathy, amotivation, and other reward processing deficits. To date, empirical support for these effects is limited, and no previous studies have assessed both acute effects of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), as well as associations with cannabis dependence. Objectives: The objectives of this study were (1) to examine acute effects of cannabis with CBD (Cann + CBD) and without CBD (Cann-CBD) on effort-related decision-making and (2) to examine associations between cannabis dependence, effort-related decision-making and reward learning. Methods: In study 1, 17 participants each received three acute vaporized treatments, namely Cann-CBD (8 mg THC), Cann + CBD (8 mg THC + 10 mg CBD) and matched placebo, followed by a 50 % dose top-up 1.5 h later, and completed the Effort Expenditure for Rewards Task (EEfRT). In study 2, 20 cannabis-dependent participants were compared with 20 non-dependent, drug-using control participants on the EEfRT and the Probabilistic Reward Task (PRT) in a non-intoxicated state. Results: Cann-CBD reduced the likelihood of high-effort choices relative to placebo (p = 0.042) and increased sensitivity to expected value compared to both placebo (p = 0.014) and Cann + CBD (p = 0.006). The cannabis-dependent and control groups did not differ on the EEfRT. However, the cannabis-dependent group exhibited a weaker response bias than the control group on the PRT (p = 0.007). Conclusions: Cannabis acutely induced a transient amotivational state and CBD influenced the effects of THC on expected value. In contrast, cannabis dependence was associated with preserved motivation alongside impaired reward learning, although confounding factors, including depression, cannot be disregarded. This is the first well powered, fully controlled study to objectively demonstrate the acute amotivational effects of THC

Strengthening the evidence for medicinal cannabis and cannabinoids

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