Conditioned compensatory response to alcohol placebo in humans

Female drinkers are more sensitive than male drinkers to alcohol-induced heart rate increase

The present study examined the acute effect of alcohol and its cues on autonomic and cardiovascular physiology, as indexed by changes in heart rate (HR), in a relatively large sample of healthy young adult men and women. Participants (27-31 years old, final N = 145) were administered an alcoholic beverage (n = 88; 52 women) or a placebo beverage (n = 57; 35 women) in a simulated bar. Target breath alcohol concentration (BrAC) was .08 g%. HR was recorded while participants were seated alone during an initial baseline assessment in a lab room; seated with others during preparation and administration of 2 beverages in a simulated bar; and seated alone in the lab room at ascending, peak, and descending BrAC. HR increased over time for participants in both beverage groups during beverage preparation. During beverage consumption, HR decreased over time in those who drank placebo whereas HR increased over time in those who drank alcohol, increasing at a faster rate in women compared to men. HR remained elevated at the ascending, peak, and descending limb assessments only in participants who drank alcohol with HR increasing over time at ascending BrAC in the women but not men. Sex differences in HR under alcohol were not explained by sex differences in body mass index, BrAC, recent alcohol use, or subjective stimulation. Our findings suggest that women may be more sensitive to alcohol-induced increases in HR, especially in environments where alcohol cues are abundant. This may have implications for cardiovascular risks associated with alcohol. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Evidence for incentive salience sensitization as a pathway to alcohol use disorder

The incentive salience sensitization (ISS) theory of addiction holds that addictive behavior stems from the ability of drugs to progressively sensitize the brain circuitry that mediates attribution of incentive salience (IS) to reward-predictive cues and its behavioral manifestations. In this article, we establish the plausibility of ISS as an etiological pathway to alcohol use disorder (AUD). We provide a comprehensive and critical review of evidence for: (1) the ability of alcohol to sensitize the brain circuitry of IS attribution and expression; and (2) attribution of IS to alcohol-predictive cues and its sensitization in humans and non-human animals. We point out gaps in the literature and how these might be addressed. We also highlight how individuals with different alcohol subjective response phenotypes may differ in susceptibility to ISS as a pathway to AUD. Finally, we discuss important implications of this neuropsychological mechanism in AUD for psychological and pharmacological interventions attempting to attenuate alcohol craving and cue reactivity.

Characterizing conditioned reactivity to sequential alcohol-predictive cues in well-trained rats

Implicit learning about antecedent stimuli and the unconditional stimulus (US) properties of alcohol may facilitate the progressive loss of control over drinking. To model this learning, Cofresí et al. (2017) developed a procedure in which a discrete, visual conditional stimulus (houselight illumination; CS) predicted the availability of a retractable sipper that rats could lick to receive unsweetened alcohol [Alcoholism: Clinical and Experimental Research, 41, 608-617]. Here we investigated the possibility that houselight illumination, sipper presentation, and oral alcohol receipt might each exert control over alcohol seeking and drinking. We also determined the relationship between ingested dose and blood alcohol concentration, in order to validate the idea that the US is a post-ingestive action of alcohol. Finally, we tested a major prediction from the conditioning account of problematic drinking [Tomie, A., & Sharma, N. (2013). Current Drug Abuse Reviews, 6, 201-219], which is that once learned, responses elicited by a CS will promote drinking. We found that despite having constrained opportunities to drink alcohol during the conditioning procedure, ingested doses produced discriminable blood concentrations that supported cue conditioning. Based on our analysis of the dynamics of cue reactivity in well-trained rats, we found that houselight illumination triggered conditioned approach, sipper presentation evoked licking behavior, and alcohol receipt promoted drinking. Reactivity to these cues, which varied in terms of their temporal proximity to the alcohol US, persisted despite progressive intoxication or satiety. Additionally, rats with the greatest conditioned reactivity to the most distal alcohol cue were also the fastest to initiate drinking and drank the most. Our findings indicate that the post-ingestive effects of alcohol may condition multiple cues simultaneously in adult rats, and these multiple cues help to trigger alcohol seeking and drinking. Moreover, identification and characterization of these cues should be helpful for designing interventions that attenuate the power of these cues over behavior.

Situating Human Sexual Conditioning

Conditioning is often thought of as a basic, automatic learning process that has limited applicability to higher-level human behavior. In addition, conditioning is seen as separable from, and even secondary to, "innate" processes. These ideas involve some misconceptions. The aim of this article is to provide a clearer, more refined sense of human sexual conditioning. After providing some background information and reviewing what is known from laboratory conditioning studies, human sexual conditioning is compared to sexual conditioning in nonhumans, to "innate" sexual responding, and to other types of human learning processes. Recommendations for moving forward in human sexual conditioning research are included.

Immediate and Complex Cardiovascular Adaptation to an Acute Alcohol Dose

BACKGROUND

The detrimental effects of chronic heavy alcohol use on the cardiovascular system are well established and broadly appreciated. Integrated cardiovascular response to an acute dose of alcohol has been less studied. This study examined the early effects of an acute dose of alcohol on the cardiovascular system, with particular emphasis on system variability and sensitivity. The goal was to begin to understand how acute alcohol disrupts dynamic cardiovascular regulatory processes prior to the development of cardiovascular disease.

METHODS

Healthy participants (N = 72, age 21 to 29) were randomly assigned to an alcohol, placebo, or no-alcohol control beverage condition. Beat-to-beat heart rate (HR) and blood pressure (BP) were assessed during a low-demand cognitive task prior to and following beverage consumption. Between-group differences in neurocardiac response to an alcohol challenge (blood alcohol concentration ~ 0.06 mg/dl) were tested.

RESULTS

The alcohol beverage group showed higher average HR, lower average stroke volume, lower HR variability and BP variability, and increased vascular tone baroreflex sensitivity after alcohol consumption. No changes were observed in the placebo group, but the control group showed slightly elevated average HR and BP after beverage consumption, possibly due to juice content. At the level of the individual, an active alcohol dose appeared to disrupt the typically tight coupling between cardiovascular processes.

CONCLUSIONS

A dose of alcohol quickly invoked multiple cardiovascular responses, possibly as an adaptive reaction to the acute pharmacological challenge. Future studies should assess how exposure to alcohol acutely disrupts or dissociates typically integrated neurocardiac functions.

Operant responding for alcohol following alcohol cue exposure in social drinkers

INTRODUCTION

Cue reactivity paradigms have found that alcohol-related cues increase alcohol consumption in heavy drinkers and alcoholics. However, evidence of this relationship among non-alcohol dependent "social" drinkers is mixed, suggesting that individual differences must be considered when examining cue-induced drinking behavior. One important individual difference factor that might contribute to cue-induced drinking in the laboratory is the amount of alcohol that participants typically drink during occasions outside the laboratory. That is, those who typically consume more alcohol per occasion could display greater cue-induced drinking than those who typically drink less. The present study examined this hypothesis in healthy, non-dependent beer drinkers.

METHODS

The drinkers were exposed to either a series of beer images intended to prime their motivation to drink beer or to a series of non-alcoholic images of food items that served as a control condition. Following cue exposure, motivation to drink was measured by giving participants an opportunity to work for glasses of beer by performing an operant response task.

RESULTS

Results indicated that drinkers exposed to alcohol cues displayed greater operant responding for alcohol and earned more drinks compared with those exposed to non-alcohol (i.e., food) cues. Moreover, individual differences in drinking habits predicted subjects' responding for alcohol following exposure to the alcohol cues, but not following exposure to food cues.

CONCLUSIONS

The findings suggest that cue-induced drinking in non-dependent drinkers likely results in consumption levels commensurate with their typical consumption outside the laboratory, but not excessive consumption that is sometimes observed in alcohol-dependent samples.

Classical conditioning: The new hegemony

Converging data from different disciplines are showing the role of classical conditioning processes in the elaboration of human and animal behavior to be larger than previously supposed. Restricted views of classically conditioned responses as merely secretory, reflexive, or emotional are giving way to a broader conception that includes problem-solving, and other rule-governed behavior thought to be the exclusive province of either operant conditiońing or cognitive psychology. These new views have been accompanied by changes in the way conditioning is conducted and evaluated. Data from a number of seemingly unrelated phenomena such as relapse to drug abuse by postaddicts, the placebo effect, and the immune response appear to involve classical conditioning processes. Classical conditioning, moreover, has been found to occur in simpler and simpler organisms and recently even demonstrated in brain slices and in utero. This target article will integrate the several research areas that have used the classical conditioning process as an explanatory model; it will challenge teleological interpretations of the classically conditioned CR and offer some basic principles for testing conditioning in diverse areas.

Classical Conditioning: Still Going Strong

This paper summarizes developments in the field of classical conditioning. Attention is paid to four common misconceptions of what is classical conditioning. First, classical conditioning does not ensue as a simple result of temporal pairing of conditioned and unconditioned stimuli. Rather, conditioned reacting occurs if and to the degree that the subject is able to predict the occurrence of one stimulus from the presence of another one. Second, what is learned during classical conditioning is not necessarily a response to a cue, but rather a probabilistic relationship between various stimuli. Third, classical conditioning is not only manifested in responses mediated by the autonomic nervous system, but also in immunological parameters, in motoric behaviour and in evaluative judgments. Fourth, the nature of the conditioned and the unconditioned stimulus is (often) not a matter of indifference: particular combinations of CS and US produce more powerful conditioning effects than do other combinations. In the second part of the paper, the potential relevance of these developments is illustrated. Discussions are included about anxiety, addictions and food aversions/conditioned nausea.

Cue exposure in the treatment of drug dependence: the potential of a new method for preventing relapse

Cue exposure has been used successfully in the treatment of neurotic disorders. Its application to the treatment of drug dependence is founded on the premise that craving for drugs can become classically conditioned to internal and external drug-related cues and that such conditioned craving responses play an important part in relapse to drug use. This article reviews the theoretical background for the use of cue exposure, research on cue reactivity in samples of drug-dependent persons and the role of cue reactivity in relapse. What evidence exists on the clinical effectiveness of cue exposure is reviewed in some detail and a number of clinical issues relating to its practical application are discussed. It is concluded that controlled trials of the effectiveness of cue exposure treatment for drug dependence should be implemented without further delay.

Metabolic mapping of the effects of chronic voluntary ethanol consumption in rats

The 2-[14C]deoxyglucose method was used to examine the effects of chronic, voluntary ethanol consumption on rates of local cerebral glucose utilization (LCGU). LCGU was measured in male Long-Evans rats immediately following the completion of a 60-min schedule-induced polydipsia drinking session. Three groups of animals were examined: animals with a history of ethanol consumption that received ethanol on the test day (ethanol-ethanol), animals with a similar ethanol history that were presented with water on the test day (ethanol-water), and a control group that received water throughout the experiment (water-water). Ethanol consumption on the test day resulted in a highly discrete pattern of metabolic changes, with significant decreases in glucose utilization in the hippocampal complex, habenula, anterior ventral thalamus, and mammillary bodies, whereas increases were observed in the nucleus accumbens and locus coeruleus. Rates of LCGU in the ethanol-water group were increased throughout all regions of the central nervous system examined, indicating that the long-term consumption of moderate ethanol doses that do not produce physical dependence can cause significant changes in functional brain activity.

A comparison of drug conditioning and craving for alcohol and cocaine

Craving is a potentially important concept that is difficult to define and study in the laboratory. Although alcohol and cocaine are very different pharmacologically, this discussion emphasizes common factors in addiction to these drugs, such as the tendency of alcoholics and cocaine abusers to crave these substances. I review commonalities in drug conditioning and cue reactivity to alcohol and cocaine. Both drugs support Pavlovian conditioning when they are presented as unconditioned stimuli, whether studied in rodents or humans. In addition, both drugs are craved when abusers are presented with stimuli associated with these drugs. Finally, I propose a theoretical definition of craving based on autoshaping and sign-tracking phenomena that suggests a common mechanism of addiction to these drugs. This model defines craving as a reflection of sign tracking to internal and external stimuli that have in the past reliably predicted presentation of these drugs.

Reactivity to alcohol-relevant beverage and imaginal cues in alcoholics

This study was designed to explore three primary facets of reactivity to alcohol-relevant stimuli among alcoholics: (a) comparison of exposure to an alcohol-containing beverage vs. an appropriate, standardized control beverage; (b) efficacy of imaginally presented cues to elicit reactivity, alone and in combination with beverage cues; and (c) examination of the recovery process. Forty-eight male veterans attending an inpatient alcohol treatment program served as participants and were randomly assigned to one of four groups in a 2 (Alcohol vs. Lemonade Beverage) X 2 (High-Risk vs. Low-Risk Imagery) design. Heart rate reactivity to Beverage cues was consistent with previous research. An interaction of Beverage and Imagery manipulations during recovery revealed both experimental manipulations influenced heart rate, although the Alcohol/High-Risk Imagery exposure group did not demonstrate enhanced effects. Both manipulations also had an impact on ratings of desire to consume alcohol. These findings provide further support for the reliability of cue reactivity effects, and suggest the utility of imaginal exposure procedures as a component of a comprehensive cue reactivity assessment.

Different drink cues elicit different physiological responses in non-dependent drinkers

Different kinds of physiological response to stimuli which have been associated with alcohol ingestion have been observed in human subjects. A literature review shows that when subjects are exposed to alcohol associated stimuli without consuming the drinks then increases in arousal, as indexed by skin conductance and heart rate increases, tend to occur. If subjects consume drinks which have been associated with alcohol ingestion, then decreases in arousal tend to occur. Forty non-dependent drinkers were asked to either consume or hold drinks which either had a history of alcohol association or did not. Interactions were observed between the activities subjects engaged in with the drinks and the degree of alcohol association of the drinks. Presentation of alcohol associated drinks produced smaller increases in arousal than non-alcohol associated drinks if the drinks were consumed but vice versa if the drinks were just held. The results support the conclusions drawn from the literature review and have implications for current theories of conditioned responses to drug cues and the related theories of the motivational processes involved in the regulation of drug intake.

Designing studies of drug conditioning in humans

There has been much recent interest in the possibility that signals for drug use in humans acquire the ability to evoke classically conditioned (learned) states which motivate drug taking. Much data now suggest that cues paired with drug use come to elicit physiological responses and subjective reports of drug-related feelings like craving and withdrawal. However, the designs employed do not permit the conclusion that the observed responding results from classical conditioning. Studies which look directly at conditioning in the laboratory by pairing neutral stimuli with drug administration have not provided appropriate controls for unlearned effects such as sensitization or pseudo-conditioning. Similarly, studies which assess responding to cues thought to signal drug use in the natural environment (e.g., the sight of someone injecting heroin) have not adequately assessed whether such cues have unconditioned (unlearned) effects. Determining whether responding to drug-related cues results from classical conditioning has important implications for the development of drug treatments. Consequently, the purpose of the present review is to outline a set of criteria for determining that responses to drug-related stimuli in humans are learned. Existing studies are reviewed in light of these criteria and paradigms for further work are suggested.

The cue-responsivity phenomenon in dependent drinkers: 'personality' vulnerability and anxiety as intervening variables

The cue-responsivity phenomenon to alcohol-associated stimuli in dependent drinkers was examined. In accordance with previous research, significant differences on both physiological and subjective cue-responsivity variables, between dependent and non-dependent drinkers were found. The unique contribution of this paper is two-fold. Firstly, evidence is presented which suggests that the Eysenckian personality traits of introversion and neuroticism are more predictive of cue-responsivity variance in the dependent drinkers than either severity of dependence or number of years' drinking. Secondly, within this dependent group, the relationship between cue-responsivity and 'craving' was seen to be less straightforward than traditionally thought. Specifically, it suggested that it was the extent to which autonomic cue-responsivity elicited increases in self-reported anxiety, which predicted most of the variance on the 'craving' variable. Taken together, these results raise the interesting possibility that a personality disposition akin to trait anxiety, and the degree to which cue exposure elicits state anxiety, mediated the relationship between cue-responsivity and 'craving' in dependent drinkers.

Cue reactivity in alcohol abusers: stimulus specificity and extinction of the responses

Sixteen alcohol abusers who had completed detoxification were presented with seven different types of alcohol and non-alcohol related stimuli. The sight and smell of the alcoholic beverage most commonly consumed by each subject elicited the largest change in response for measures of heart rate, desire to drink, and self-reported withdrawal symptoms. Beverages progressively more different from the preferred one produced responses of consistently lower magnitude. In the second phase of the study, 10 subjects were exposed to 20 presentations of the sight and smell of their preferred drink. A gradual reduction in the magnitude of the response for all three measures was observed over the 20 presentations. These results were discussed in terms of a conditioning interpretation of cue reactivity. They indicate the need for cue exposure programs to be based on the particular drinking history of the individual.

Conditioned learning in alcohol dependence: implications for cue exposure treatment

A review of the literature pertinent to cue exposure treatment in alcohol dependence is presented. Psychological models of relapse, based on conditioning and social learning theories, are critically evaluated. In particular, attention is drawn to the potential implications for cue exposure research and treatment of an interaction between Pavlovian and operant conditioning, problems with the application of the concepts of arousal and craving and the importance of a systems model to understand physiological responses. It is concluded that no study has so far demonstrated a link between conditioned responses to alcohol-related cues and relapse, an assumption on which cue exposure treatment is based. Further, the evidence for the effectiveness of cue exposure as a treatment is lacking. Promising research directions are identified.

Alcoholism and panic disorder: is the comorbidity more than coincidence?

Studies on alcoholic patients have found a higher than expected prevalence of panic disorder, and suggest a positive correlation between the level of alcohol consumption and severity of anxiety. Conversely, there is an increased prevalence of alcoholism among patients with panic disorder and their blood relatives. A comparison of symptoms, physiological and neurochemical changes known to occur in both alcohol withdrawal and panic disorder reveals a degree of similarity between the 2 conditions. Based on the data, we propose that the chemical and cognitive changes occurring as the result of repeated alcohol withdrawals may kindle and condition coincidence of panic attacks in susceptible individuals. Implications of our postulates for treatment of alcohol withdrawal and panic disorder in alcoholics and for future studies are discussed.

Factors regulating ethanol tolerance

Ethanol tolerance is a complex phenomenon. Its development is governed by pharmacological and behavioural, as well as genetic factors. The doses of ethanol employed and the duration of ethanol treatment are important pharmacological variables. Behavioural factors such as experience of intoxication and Pavlovian conditioning may also affect the development or manifestation of ethanol tolerance. Genetic factors can influence the development of tolerance directly or/and indirectly through its influence on the initial sensitivity to ethanol. The relevance and implication of tolerance, particularly conditioned tolerance in alcohol abuse and alcoholism, are discussed.

Conditioned opponent responses: effects of placebo challenge in alcoholic subjects

The present study continues a series of studies examining a number of variables that contribute to the demonstration of conditioned responses to alcohol in alcoholics. We pursued here the hypothesis that subjects receiving placebo in an environment previously associated with alcohol ingestion would exhibit conditioned responses as compared with subjects who had only received placebo in the environment. Further, we predicted that these conditioned responses would be opposite in direction to responses obtained during active drink sessions. Twelve subjects received active alcohol during session Days 1 through 4 and a placebo challenge on Day 5; the second group received placebo throughout sessions 1 through 5. On Day 1, heart rate and skin conductance were elevated following active alcohol ingestion as compared with placebo. On Day 5 following the placebo challenge, these physiological responses were significantly lower in the alcohol group as compared with the placebo group; the reversal of effects on Day 5 is suggestive of conditioned compensatory responses. Also, following the placebo on Day 5, desire to drink scores of the alcohol group were greater than those of the placebo group. The present data suggest that subjects exhibit conditioned compensatory responses when the environment signals alcohol availability. Results are consistent with Siegel's model of conditioned compensatory responses to repeated drug administration, and may help to account for some aspects of tolerance development and conditioned withdrawal.

Psychophysiological effects of alcohol-related stimuli: II. Enhancement with alcohol availability

This laboratory study examined methods of enhancing physiological and subjective responses of alcoholics to naturalistic alcohol-related stimuli by repeated exposures to a high-dose alcohol drink. Individual subjects participated in five successive daily sessions consisting of randomized-block presentations of gustatory and visual presentation of alcohol, pepper juice (as a control for stimulus taste intensity), or water stimuli. Following the stimulus trial series, all subjects ingested 1.5 oz of alcohol in a shot glass. Twelve subjects next received a 1.7 g/kg alcohol drink ("high dose alcohol group") on Days 1-4 and placebo on Day 5, and 12 subjects received a placebo drink on all study Days (1-5) ("placebo drink group"). On Day 1, alcohol stimuli generally elicited larger heart rate and skin conductance increases and skin temperature decreases than water or pepper juice stimuli. Alcohol stimuli also elicited greater subjective responses than either pepper juice or water. Alcohol availability within the taste trial markedly increased physiological and subjective reactivity to alcohol-related stimuli, perhaps due to the closer approximation to natural drinking behavior. A comparison with previous data from this laboratory suggests that prestudy deprivation from alcohol, instructions to expect alcohol, a conductive drink setting, and the opportunity to drink alcohol within the session may enhance reactivity to alcohol stimuli in alcoholics.

Psychophysiological effects of alcohol-related stimuli: I. The role of stimulus intensity

The present study extends previous research on conditioning factors in the physiological and subjective responses to naturalistic alcohol-related stimuli. Specifically, the effects of differential alcohol ingestion histories and of stimulus intensity were examined on the occurrence of conditioned responses in the laboratory. Twelve alcoholic subjects and twelve moderate drinkers participated in a single experimental session consisting of randomized presentations of three types of stimulus trials. Each trial included gustatory and visual presentation of alcohol, pepper juice (as a control for stimulus intensity) or water. Both alcohol and pepper juice stimuli significantly increased heart rate and skin conductance responses as compared with water stimuli. In contrast, subjects significantly increased self-report ratings of high and feel different following alcohol stimuli only. Physiological and subjective responses were similar in alcoholics and social drinkers with the exception of significantly higher self-reported craving in alcoholic subjects. These findings suggest that stimulus intensity contributes to the magnitude of physiological but not subjective responses to alcohol-related stimuli.