Interventions for tobacco use cessation in people living with HIV and AIDS

Background: Tobacco use is highly prevalent amongst people living with HIV/AIDS (PLWHA) and has a substantial impact on morbidity and mortality. Objectives: To assess the effectiveness of interventions to motivate and assist tobacco use cessation for people living with HIV/AIDS (PLWHA), and to evaluate the risks of any harms associated with those interventions. Search methods: We searched the Cochrane Tobacco Addiction Group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and PsycINFO in June 2015. We also searched EThOS, ProQuest, four clinical trial registries, reference lists of articles, and searched for conference abstracts using Web of Science and handsearched speciality conference databases. Selection criteria: Controlled trials of behavioural or pharmacological interventions for tobacco cessation for PLWHA. Data collection and analysis: Two review authors independently extracted all data using a standardised electronic data collection form. They extracted data on the nature of the intervention, participants, and proportion achieving abstinence and they contacted study authors to obtain missing information. We collected data on long-term (greater than or equal to six months) and short-term (less than six months) outcomes. Where appropriate, we performed meta-analysis and estimated the pooled effects using the Mantel-Haenszel fixed-effect method. Two authors independently assessed and reported the risk of bias according to prespecified criteria. Main results: We identified 14 studies relevant to this review, of which we included 12 in a meta-analysis (n = 2087). All studies provided an intervention combining behavioural support and pharmacotherapy, and in most studies this was compared to a less intensive control, typically comprising a brief behavioural intervention plus pharmacotherapy. There was moderate quality evidence from six studies for the long-term abstinence outcome, which showed no evidence of effect for more intense cessation interventions: (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.72 to 1.39) with no evidence of heterogeneity (I 2 = 0%). The pooled long-term abstinence was 8% in both intervention and control conditions. There was very low quality evidence from 11 studies that more intense tobacco cessation interventions were effective in achieving short-term abstinence (RR 1.51, 95% CI 1.15 to 2.00); there was moderate heterogeneity (I 2 = 42%). Abstinence in the control group at short-term follow-up was 8% (n = 67/848) and in the intervention group was 13% (n = 118/937). The effect of tailoring the intervention for PLWHA was unclear. We further investigated the effect of intensity of behavioural intervention via number of sessions and total duration of contact. We failed to detect evidence of a difference in effect according to either measure of intensity, although there were few studies in each subgroup. It was not possible to perform the planned analysis of adverse events or HIV outcomes since these were not reported in more than one study. Authors' conclusions: There is moderate quality evidence that combined tobacco cessation interventions provide similar outcomes to controls in PLWHA in the long-term. There is very low quality evidence that combined tobacco cessation interventions were effective in helping PLWHA achieve short-term abstinence. Despite this, tobacco cessation interventions should be offered to PLWHA, since even non-sustained periods of abstinence have proven benefits. Further large, well designed studies of cessation interventions for PLWHA are needed

Electrophysiological correlates of associative learning in smokers: a higher-order conditioning experiment

Background: Classical conditioning has been suggested to play an important role in the development, maintenance, and relapse of tobacco smoking. Several studies have shown that initially neutral stimuli that are directly paired with smoking are able to elicit conditioned responses. However, there have been few human studies that demonstrate the contribution of higher-order conditioning to smoking addiction, although it is assumed that higher-order conditioning predominates learning in the outside world. In the present study a higher-order conditioning task was designed in which brain responses of smokers and non-smokers were conditioned by pairing smoking-related and neutral stimuli (CS1smokeand CS1neutral) with two geometrical figures (CS2smokeand CS2neutral). ERPs were recorded to all CSs.Results: Data showed that the geometrical figure that was paired with smoking stimuli elicited significantly larger P2 and P3 waves than the geometrical figure that was paired with neutral stimuli. During the first half of the experiment this effect was only present in smokers whereas non-smokers displayed no significant differences between both stimuli, indicating that neutral cues paired with motivationally relevant smoking-related stimuli gain more motivational significance even though they were never paired directly with smoking. These conclusions are underscored by self-reported evidence of enhanced second-order conditioning in smokers.Conclusions: It can be concluded that smokers show associative learning for higher-order smoking-related stimuli. The present study directly shows the contribution of higher-order conditioning to smoking addiction and is the first to reveal its electrophysiological correlates. Although results are preliminary, they may help in understanding the etiology of smoking addiction and its persistence

Altering the Motivational Function of Nicotine through Conditioning Processes

The collection of chapters in this 55th Nebraska Symposium on Motivation Volume clearly highlights that effective strategies for reducing compulsive tobacco use will require a multifaceted approach in which genetic, neurobiological, individual, and cultural factors are considered. It is difficult, if not impossible, to predict where the next important breakthrough will come from (Bevins & Bardo, 2004; Dethier, 1966; Laidler, 1998). Accordingly, further research that extends and challenges current theory and practice at each of these levels of analysis is needed. The continuing focus of our research program, and the topic of the present chapter, is on the role of Pavlovian conditioning processes involving nicotine. Theoretical and empirical approaches to nicotine dependence that include Pavlovian conditioning processes have lead to important advances in our understanding and treatment of chronic tobacco use (e.g., see Rose, Chapter 8 and Tiffany, Warthen, & Goedecker, Chapter 10 in current Volume). These approaches conceptualize the drug as an unconditioned stimulus (US) or reinforcer. That is, the pharmacological effects of the drug (e.g., reward, analgesia, psychomotor stimulation) enter into an association with stimuli that reliably co-occur with these effects (e.g., paraphernalia, situational cues). Later exposure to these conditioned stimuli (CSs) can evoke conditioned responses (CRs) that increase the chances an individual will seek drug. More recently, we have suggested that the interoceptive stimulus effects of nicotine might also serve as a CS for other appetitive non-drug outcomes (i.e., USs) and/or a stimulus that occasions whether other CS-US associations will or will not occur (i.e., an occasion setter or facilitator; see Bevins & Palmatier, 2004). We have further suggested that such an associative learning history could impact the tenacity of nicotine addiction—e.g., shorten the time between experimentation and dependence, increase the difficulty of quitting, make sustaining abstinence more difficult, etc. At the current time these suggestions are speculative. With this in mind, the present chapter will review the research in this area, as well as highlight some of its historical precursors and suggest some possible future directions for research. In doing so, hopefully the reader will gain an appreciation for how this approach might lead to further insight into how Pavlovian conditioning processes can alter the motivational function of nicotine in a manner that contributes to chronic tobacco use