Eye movements to smoking-related cues: effects of nicotine deprivation

RATIONALE: According to recent theories of addiction, nicotine deprivation may influence biases in the orienting and maintenance of attention on smoking-related cues. OBJECTIVES: We examined the effect of nicotine deprivation on different aspects of attentional biases for smoking-related cues. METHODS: Smokers' eye movements to smoking-related and control pictures were assessed during a visual probe task under deprived and non-deprived conditions. RESULTS: When deprived, smokers maintained their gaze for longer on smoking-related than control cues, relative to when non-deprived. Deprivation also increased craving and pleasantness ratings of smoking cues. Across both deprived and non-deprived conditions, smokers were more likely to shift their gaze towards smoking cues and were faster to respond to probes replacing smoking cues, relative to non-smoking cues, but these attentional bias measures were not significantly affected by the deprivation manipulation. CONCLUSIONS: Results suggest a selective effect of deprivation on the maintenance of attention on smoking-related cues.     

The Questionnaire of Smoking Urges is sensitive to abstinence and exposure to smoking-related cues

The Questionnaire of Smoking Urges (QSU) was designed to measure cravings elicited by abstinence from cigarette smoking. In the present study, the sensitivity of the QSU both to brief periods of abstinence and to exposure to smoking-related cues was investigated. A progressive ratio (PR) operant procedure was also employed, in which behaviour was maintained either by primary reinforcement (puffs on a cigarette) or by secondary reinforcement (tokens exchanged later for puffs on a cigarette) in separate experiments. Dependent smokers, who were not abstinent or who were abstinent for either 2 or 4 h, were tested in both a cue-rich and a no-cue environment. The results indicated that the QSU was sensitive both to brief periods of abstinence and to exposure to smoking-related cues, but the effect of smoking-related cues on QSU scores was maximal in non-abstinent smokers. In contrast, neither abstinence nor exposure to smoking-related cues significantly influenced the number of reinforcers earned, or the number of responses made, in either PR task. However, there was a significant interaction between gender and degree of abstinence on PR performance under primary reinforcement, and correlations between PR and QSU measures that were dependent on a complex interaction between the presence/absence of smoking-related cues and the type of reinforcer used. These results suggest that the QSU is sensitive to subtle influences on subjective urges to smoke in dependent smokers and, although PR measures are relatively insensitive to these influences, there is some evidence that PR performance is related to subjective measures of the urge to smoke.     

Counteracting depressant effects of alcohol by psychological stress

Interaction between effects of acute alcohol intoxication and psychological stress was examined in 8 male and 8 female students. Alcohol was given as whisky, 2 ml/kg body wt to males and 1.7 ml/kg body wt to females. Psychological stress was induced by applying electric shocks of a moderate intensity to two fingers of one of the subject's hands. Performance in reaction-time tasks representing different levels of complexity, self-estimates of wakefulness and mood, measurements of catecholamine excretion and of heart rate, were used as indices of the effects caused by alcohol and shock, singly and in combination. Among these variables, only performance was selectively sensitive to the different experimental treatments. Thus, shocks and alcohol had opposite effects, shocks decreasing and alcohol increasing reaction time. When the subjects were simultaneously exposed to both influences, the impairment produced by alcohol was significantly reduced by shock at all levels of task complexity. No sex differences could be detected.Stay in Stockholm sponsored by fellowships from the European Training Program in Brain and Behaviour Research and from the International Federation of University Women.The investigation was supported by grants from the Swedish Medical Research Council (Project No. 997) and the Swedish Council for Social Science Research. We wish to thank Dr. A.-L. Myrsten for valuable suggestions in designing the experiment.     

Influence of negative affect on selective attention to smoking-related cues and urge to smoke in cigarette smokers

According to recent models of addiction, negative affect plays an important role in maintaining drug dependence. The study investigated the effect of negative mood on attentional biases for smoking-related cues and smoking urge in cigarette smokers. Eye movements to smoking-related and control pictures, and manual response times to probes, were recorded during a visual probe task. Smoking urges and mood were assessed by self-report measures. Negative affect was manipulated experimentally as a within-participants independent variable; that is, each participant received negative and neutral mood induction procedures, in counterbalanced order in separate sessions, before the attentional task. There were two groups of participants: smokers and nonsmokers. Smokers showed (i) a greater tendency to shift gaze initially towards smoking-related cues, and (ii) greater urge to smoke when they were in negative mood compared with neutral mood. Manual response time data suggested that smokers showed a greater tendency than nonsmokers to maintain attention on smoking-related cues, irrespective of mood. The results offer partial support for the view that negative mood increases selective attention to drug cues, and urge to smoke, in smokers. The findings are discussed in relation to an affective processing model of negative reinforcement in drug dependence.     

Selective processing of smoking-related cues in current smokers, ex-smokers and never-smokers on the modified Stroop task

The aim of this study was to investigate selective processing biases towards smoking-related stimuli in relation to acute abstinence and smoking history. Differences in the processing of smoking-related and control cues in current smokers, ex-smokers and never-smokers on the modified Stroop task were investigated, with smokers randomized to either abstain or smoke normally for a period of 24 h. The results indicated no significant effect of deprivation (abstinent versus non-abstinent smokers), or of smoking history (ex- versus never-smokers) on colour-naming times for smoking-related versus control words. However, there was a significant effect of smoking status (current versus non-smokers) on colour-naming times for smoking words compared to control words (i.e. slower colour-naming of smoking-related words in smokers). This effect approached significance when stimuli were presented in a masked exposure condition. Among smokers, colour-naming interference was associated with the personality trait of Sensitivity to Reward. These results indicate a processing bias for smoking-related cues in current smokers. However, this bias does not appear to be a permanent feature of nicotine addiction, given the lack of difference between ex-smokers and never-smokers.     

The effects of atropine on changes in the sleep patterns induced by psychological stress in rats

The present study was designed to investigate the acute effects of psychological stress on the sleep patterns of rats and the potential mechanisms underlying these effects. Psychological stress was induced using a communication box. In a preliminary study, sleep recording was performed for 6 h immediately after 1-h stress in rats. The results showed that psychological stress significantly enhanced the total amount of rapid eye movement (REM) sleep by prolonging the average duration of REM sleep episodes during first 3 h of sleep, whereas the total amount of non-rapid eye movement sleep was not influenced. In a second study, three doses of atropine (3, 10, or 30 nmol) were intracerebroventricularly microinjected into the rats. Total REM sleep was inhibited by the highest dose of atropine during the first 3 h of sleep in the stressed group but not in the control group; the inhibition of total REM sleep was due to a reduction in the average duration of REM sleep episodes. These results suggest that the increase in total REM sleep induced by stress was related to the activation of cholinergic neurons. In addition, plasma corticosterone--an index of hypothalamic-pituitary-adrenal (HPA) axis activity in response to stress--was examined after psychological stress. The concentration of corticosterone did not change significantly. Therefore, the abnormal sleep patterns could not be simply attributed to the HPA axis. These results indicate that the changes in sleep patterns induced by stress were related to cholinergic neurons, but not the HPA axis.     

Effects of acute tyrosine depletion on subjective craving and selective processing of smoking-related cues in abstinent cigarette smokers

We investigated the impact of the administration of a tyrosine-depleting amino acid mixture compared to a balanced mixture on measures of mood, craving and selective processing of smoking-related cues in healthy cigarette smokers instructed to abstain from smoking for 12 h prior to, and during, the experiment. A modified stroop task was used to index selective processing of smoking-related cues. We observed evidence for an increase in subjective craving among males, and an attenuation of the selective processing of smoking-related cues compared to control cues among females, in the tyrosine-depleting condition compared to the balanced condition. No effects of mixture were observed on measures of subjective mood. These results tentatively support for the role of dopaminergic neurotransmission in mediating the response of cigarette smokers to smoking-related cues. In addition, these results also provide further evidence for sex differences in the factors that maintain cigarette smoking, in particular with respect to conditioned reinforcement of smoking behaviour, and suggest that the relationship between subjective craving and selective processing of smoking-related cues may differ in males and females.     

The effects of exercise on cigarette cravings and brain activation in response to smoking-related images

Rationale

Smokers show heightened activation toward smoking-related stimuli and experience increased cravings which can precipitate smoking cessation relapse. Exercise can be effective for modulating cigarette cravings and attenuating reactivity to smoking cues, but the mechanism by which these effects occur remains uncertain.

Objective

The objective of the study was to assess the effect of exercise on regional brain activation in response to smoking-related images during temporary nicotine abstinence.

Methods

In a randomised crossover design, overnight abstinent smokers (n?=?20) underwent an exercise (10-min moderate-intensity stationary cycling) and passive control (seating for the same duration) treatment, following 15?h of nicotine abstinence. After each treatment, participants underwent functional magnetic resonance imaging (fMRI) brain scanning while viewing a random series of blocked smoking or neutral images. Self-reported cravings were assessed at baseline, mid-, and post-treatments.

Results

There was a significant interaction effect (treatment?×?time) for desire to smoke, F (2,32)?=?12.5, p?Conclusion The study shows differing activation towards smoking images following exercise compared to a control treatment and may point to a neuro-cognitive process following exercise that mediates effects on cigarette cravings.     

The psychological stress model using motor suppression

Psychological stress is believed to be implicated in the etiology of affective disorders such as anxiety and depression. To date, a wide range of behavioral responses including analgesia and motor suppression induced by various physiological stressors such as footshock, forced swimming and immobilization have been investigated in animals. However, there is little information concerning behavioral changes in psychological stress. This article describes the experimental procedures and the characteristics of motor suppression in psychological stress, defined as conditioned fear stress (CFS). Mice exhibit a marked suppression of motility when they are re-placed in the same environment in which they had previously received an electric footshock. This motor suppression is regarded as a conditioned emotional response to the environment associated with previous footshock. The motor suppression in CFS is attenuated by sigma receptor agonists such as (+)-N-allylnormetazocine and dextromethorphan, whereas typical anxiolytics (diazepam and chlordiazepoxide) and antidepressants (imipramine and fluoxetine) have no effect. These findings suggest that the CFS model may be useful for investigating the pathogenesis of affective disorders, particularly those considered to be treatment resistant, and for developing their novel therapeutic drugs.     

Neural substrates of acupuncture in the modulation of cravings induced by smoking-related visual cues: an FMRI study

Rationale

Cue reactivity is a key factor in modulating motivational and goal-directed behaviors associated with compulsive drug intake and relapse. Smoking-associated cues produce smoking urges and cravings and are accompanied by the activation of brain regions involved in attention, motivation, and reward.

Objectives

We investigated whether acupuncture ameliorates cravings induced by smoking-related visual cues, and we explored the neural mechanisms underlying the effects of acupuncture on modulating smoking urges.

Methods

After 36 h of smoking abstinence, 25 right-handed male smokers underwent fMRI, during which smoking-related and neutral visual cues were presented. Twelve subjects were treated with real acupuncture (RA) at HT7 and 13 subjects received sham acupuncture (SA). During the scanning sessions, craving scores to smoking-related visual cues were assessed before and after RA or SA treatment. The differences in brain responses to smoking vs. neutral cues after treatment between the RA and SA groups were detected using three-way ANOVAs (Cue × Session × Group).

Results

After treatment, the craving scores were significantly decreased in the RA group, as compared to the SA group. When we explored the neural substrates of acupuncture on the modulation of cravings induced by smoking cues, significant differences were found in the medial prefrontal cortex, the premotor cortex, the amygdala, the hippocampus, and the thalamus.

Conclusions

These findings suggest that acupuncture alleviates cue-induced cravings through the regulation of activity in brain regions involved in attention, motivation, and reward relative to craving scores in the initial abstinence phase.     

不同治法方药对慢性心理应激大鼠下丘脑CRH mRNA表达的影响

目的　从分子水平研究不同治法方药调控慢性心理应激反应的作用机制。方法　采用慢性束缚心理应激大鼠模型 ,RT PCR法分析应激大鼠下丘脑CRHmRNA的表达及不同治法方药的影响。结果　连续 2wk的慢性束缚心理应激大鼠下丘脑中CRHmRNA表达明显升高 (P <0 0 1) ,调肝和补肾治法方药可以明显地降低下丘脑CRHmRNA表达 (P <0 0 1orP <0 0 5 ) ,而健脾治法方药对此则无调节作用。结论　调肝和补肾治法方药可以通过降低下丘脑CRHmRNA表达 ,有效地调控慢性心理应激反应。     

Effects of acute tyrosine/phenylalanine depletion on the selective processing of smoking-related cues and the relative value of cigarettes in smokers

Rationale Acute tyrosine/phenylalanine depletion (ATPD) is a validated neurobiological challenge that results in reduced dopaminergic neurotransmission, allowing examination of the effects of a hypodopaminergic state on craving-related processes. Objectives We studied 16 nonabstaining smokers (>10 cigarettes/day; 9 males; age 20–33 years) to whom was administered a tyrosine/phenylalanine-free mixture (TYR/PHE-free) and a balanced amino acid mixture (BAL) in a double-blind, counterbalanced, crossover design. Methods Subjective cigarette craving, attentional bias to smoking-related word cues, relative value of cigarettes, negative mood, and expired carbon monoxide (CO) levels were measured at various timepoints through 300 min. Participants smoked at hourly intervals to prevent acute nicotine withdrawal during testing. Results The TYR/PHE-free mixture, as compared to the BAL mixture, was associated with a greater increase in CO levels from baseline (p = 0.01). Adjusting for the potential confounding influence of between-condition differences in CO levels across time, TYR/PHE-free mixture was associated with increased demand for cigarettes (p = 0.01) and decreased attentional bias toward smoking-related words (p = 0.003). There were no significant differences between conditions in either subjective craving or depressed or anxious mood (p values > 0.05). Conclusion Among nonabstaining daily smokers, acute dopaminergic depletion via ATPD may influence smoking behavior and indices of smoking-related motivation, such as attentional bias to smoking cues and relative cigarette value, which are not readily captured by subjective craving.     

The psychological and physiological effects of MDMA on normal volunteers

The experimental subjects were older than the average general population, more educated and considerably experienced in drug use. They considered themselves to have benefited by their MDMA experience, with no evidence of harm. There were moderate, consistent biochemical, cardiovascular and neurobehavioral changes within normal limits that peaked between one and two hours following ingestion, returning to predrug levels within 24 hours. This experimental situation produced no observed or reported psychological or physiological damage, either during the 24-hour study period or during the three-month follow-up period. While the subjects are not typical of the general population, the findings support the general impression among knowledgeable professionals that MDMA is reasonably safe, produces positive mood changes in users, does not cause negative problems (if used sparingly and episodically) and is without evidence of abuse. Certainly, any drug that causes ataxia, elevates blood pressure and pulse is potentially unsafe. One can say little about safety when effects and side effects are studied for only 24 hours and then a blood cytology is obtained after three months. In this study, safety must exclude long-term toxicity. Not enough is known about MDMA's long-range effects other than information from random anecdotal evidence supplied by a few clinicians plus self-reports by unselected and unsupervised users. From the information presented here, one can only say that MDMA, at the doses tested, has remarkably consistent and predictable psychological effects that are transient and free of clinically apparent major toxicity. The experimental subjects believed that MDMA is both safe and beneficial, but there is insufficient evidence to accurately judge either the drug's potential harm or benefit.     

心理干预对乳腺癌手术患者的影响

目的探讨心理干预对乳腺癌手术患者心理的影响。方法将80例患者随机分为观察组和对照组各40例,对照组采用常规护理,观察组在常规护理的基础上采用心理护理,观察两组患者的配合治疗程度和焦虑程度。结果观察组配合治疗程度和焦虑程度明显优于对照组,差异有统计学意义（P〈0.05）。结论心理干预能促进乳腺癌手术患者的康复,值得临床推广。     

Selective processing of smoking-related cues in smokers: manipulation of deprivation level and comparison of three measures of processing bias

Recent theories of addiction suggest that an attentional bias for drug-related cues plays an important role in maintaining drug-taking behaviours. A key feature of the present study is that it used three different measures of processing bias for linguistic and pictorial smoking-related cues: masked and unmasked conditions of the modified Stroop task, and a pictorial version of the visual probe task. Participants were smokers (n = 27), who were tested twice, with deprivation level manipulated as a within-subjects variable. They were asked to abstain from smoking for 12 h before one session, and to smoke normally before the other. Results were consistent with an attentional bias for smoking-related pictures on the visual probe task, and for smoking-related words in the unmasked condition of the modified Stroop task. The latter bias was most strongly predicted by self-reported urge to smoke, rather than by the deprivation manipulation. There was no evidence of a preconscious bias for smoking cues. The three measures of cognitive bias (from masked and unmasked Stroop and visual probe tasks) were not significantly correlated with each other, which suggests they may tap different underlying mechanisms. We discuss the results with respect to conceptualizations of selective attention, addiction and motivational states in general.     

The effects of sensory deprivation on cigarette craving and smoking behaviour

Seventy two heavy smokers were treated by means of either 6, 12 or 24 hours of sensory deprivation, or by 24 hours of social isolation. There was a signigicant linear trend relating time in confinement to reduction in mean post-treatment smoking rate. A measure of cigarette craving while confined did not predict treatment outcome. Craving while confined for 24 hours exhibited a cubic trend, indicating a diurnal rhythm. Differences between the two 24 hour conditions were nonsignificant, but suggested that social isolation may be therapeutically preferable to sensory deprivation.