Brian Eastwood

Experimental manipulation of attentional bias increases the motivation to drink alcohol

RationaleAttentional bias for alcohol-related cues is associated with the motivation to drink alcohol, possibly because attentional bias increases craving.ObjectivesWe examined whether an experimentally induced attentional bias would influence subjective and behavioural indices of the motivation to drink.MethodsHeavy social drinkers (N=40) completed an attentional training procedure, in which half of the participants were trained to direct their attention towards alcohol-related cues (‘attend alcohol’), and half of the participants were trained to direct their attention away from alcohol-related cues (‘avoid alcohol’). After attentional training, participants rated their urge to drink alcohol, and the amount of beer consumed during a taste test was measured.ResultsThe attentional training procedure produced significant changes in attentional bias in the predicted direction in both experimental groups. Attentional training produced an increase in the urge to drink alcohol in the attend alcohol group, and the attend alcohol group consumed more beer than the avoid alcohol group during the taste test.ConclusionsThese results suggest that a potentiated attentional bias for alcohol-related cues can increase the motivation to drink alcohol. Theoretical and clinical implications are discussed.

Experimental manipulation of attentional biases in heavy drinkers: do the effects generalise?

RationaleIn heavy drinkers, training attention towards alcohol cues increases alcohol craving, but it is not clear if effects of ‘attentional training’ generalise to novel stimuli and measurement procedures.ObjectivesWe investigated possible generalisation of attentional training to novel alcohol cues and other methods of measuring cognitive bias.Materials and methodsA modified visual probe task was used to train participants to direct their attention either towards (‘attend alcohol’ group) or away from (‘avoid alcohol’ group) alcohol cues; attentional bias was not manipulated in a control group (total N = 60). After attentional training, we measured cognitive bias (using visual probe, modified Stroop, flicker-induced change blindness and stimulus–response compatibility tasks), alcohol craving and alcohol consumption.ResultsAttentional bias for alcohol cues increased in the ‘attend alcohol’ group, and this effect generalised to novel stimuli, but not to other cognitive bias tasks. In the ‘avoid alcohol’ group, attentional bias was reduced for the stimuli that were used during attentional training, but these effects did not generalise to different stimuli or cognitive bias tasks. Alcohol craving increased among participants in the ‘attend alcohol’ group, but only among participants who were aware of the experimental contingencies during attentional training. There were no group differences in alcohol consumption.ConclusionsThe effects of attentional training show limited generalisation to different alcohol cues and methods of measuring cognitive bias. Experimentally increased attentional bias seems to increase subjective craving, but only among participants who are aware of the experimental contingencies that were in place during attentional training.

Activation of mesolimbic dopamine neurons during novel and daily limited access to palatable food is blocked by the opioid antagonist LY255582.

An analog of the trans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidine series (LY255582) exhibits high in vitro binding affinity and antagonist potency for the mu-, delta-, and kappa-opioid receptors. In vivo, LY255582 exhibits potent effects in reducing food intake and body weight in several rodent models of obesity. In the present study, we evaluated the effects of LY255582 to prevent the consumption of a highly palatable (HP) diet (a high-fat/high-carbohydrate diet) both when the food was novel and following daily limited access to the HP diet. Additionally, we examined the effects of consumption of the HP diet and of LY255582 treatment on mesolimbic dopamine (DA) signaling by in vivo microdialysis. Consumption of the HP diet increased extracellular DA levels within the nucleus accumbens (NAc) shell. Increased DA in the NAc shell was not related to the quantity of the HP diet consumed, and the DA response did not habituate following daily scheduled access to the HP diet. Interestingly, treatment with LY255582 inhibited consumption of the HP diet and the HP diet-associated increase in NAc shell DA levels. Moreover, the increased HP diet consumption observed following daily limited access to the HP diet was completely prevented by LY255582 treatment. LY255582 may be a useful tool in understanding the neural mechanisms involved in the reinforcement mechanisms regulating food intake.

Investigating the effects of a craving induction procedure on cognitive bias in cannabis users

In tobacco smokers and heavy drinkers, the manipulation of subjective craving influences the biased cognitive processing of substance-related cues. In the present study, we used a within-subjects design to examine the effects of a cannabis craving-induction procedure (imagery scripts and cannabis-related videos) on craving and cognitive biases for cannabis cues, in a sample of regular cannabis users (N = 33). Results indicated that the craving induction procedure produced the predicted increases in subjective craving (as assessed with the Marijuana Craving Questionnaire), although the effect size was small and effects were not maintained for the duration of the laboratory session. Although cognitive biases (attentional, approach, and perceived pleasantness) were observed for cannabis-related cues relative to control stimuli, these were not significantly influenced by the craving manipulation. Theoretical implications and methodological issues are discussed.