Alcohol and marijuana: comparative dose effect profiles in humans

This study compared subjective and performance dose effect profiles of oral alcohol and smoked marijuana. Male subjects (N = 6) with histories of moderate alcohol and marijuana use received three doses of alcohol (0, 0.6, 1.2 g/kg) and three doses of marijuana (0, 1.3, 2.7% delta 9-THC) in a double-blind, randomized crossover design. Physiological indices indicated that active drug was delivered to subjects dose dependently. Alcohol produced dose-related elevations on several subjective measures of drug effect. The high dose of alcohol impaired performance on circular lights, tracking and digit-symbol substitution (DSST) tasks, whereas the low alcohol dose impaired only circular lights performance. Marijuana produced elevations on subjective report measures, but effects were similar for the two active doses. Minimal performance impairment was seen with marijuana on only one measure (DSST speed). The subjective and performance effect profiles produced by smoked marijuana were similar to that of the low (0.6 g/kg) dose of alcohol. These data are useful for understanding the relative performance impairment produced by alcohol and marijuana and the relationship between their subjective and behavioral effects.     

Behavioral effects of alcohol in novice and experienced drinkers: alcohol expectancies and impairment

This study was designed to test the hypothesis that the relation between an individual's expected and actual impairment under alcohol develops as a function of drinking experience. Fourteen early stage, novice (N) and 14 experienced (E) male social drinkers participated in the research. Group N had been drinking for 20 months or less (mean =8.1 months). Group E subjects had been drinkers for 24 or more (mean =42.7 months). All subjects practised a task that measured psychomotor skill (pursuit rotor) and rated the degree to which alcohol was expected to impair their performance on the task. Half of the subjects in each group then performed the task under alcohol (0.56 g/kg). The remainder served as controls and received no beverage prior to performing the task. In accord with the hypothesis, experienced drinkers who expected more impairment performed more poorly under alcohol, whereas novice drinkers' expected and actual impairment were not related. In addition, when novice and experienced drinkers received no beverage, their expectations were unrelated to their drug-free performance. Thus alcohol expectancies were not relevant to performance in a non-drinking situation. These findings contribute new information identifying drinking history as an important factor strengthening the relationship between expectations about the effect of alcohol and behavior under the drug.     

Development and Preliminary Validation of the Drinking Expectancy Sexual Vulnerabilities Questionnaire (DESV-Q): A Purpose-Specific Instrument for Rape-Perception Research

Background: Alcohol expectancies likely play a role in people's perceptions of alcohol-involved sexual violence. However, no appropriate measure exists to examine this link comprehensively. Objective: The aim of this research was to develop an alcohol expectancy measure which captures young adults' beliefs about alcohol's role in sexual aggression and victimization. Method: Two cross-sectional samples of young Australian adults (18–25 years) were recruited for scale development (Phase 1) and scale validation (Phase 2). In Phase 1, participants (N = 201; 38.3% males) completed an online survey with an initial pool of alcohol expectancy items stated in terms of three targets (self, men, women) to identify the scale's factor structure and most effective items. A revised alcohol expectancy scale was then administered online to 322 young adults (39.6% males) in Phase 2. To assess the predictive, convergent, and discriminant validity of the scale, participants also completed established measures of personality, social desirability, alcohol use, general and context-specific alcohol expectancies, and impulsiveness. Results: Principal axis factoring (Phase 1) and confirmatory factor analysis (Phase 2) resulted in a target-equivalent five-factor structure for the final 66-item Drinking Expectancy Sexual Vulnerabilities Questionnaire (DESV-Q). The factors were labeled (1) Sexual Coercion, (2) Sexual Vulnerability, (3) Confidence, (4) Self-Centeredness, and (5) Negative Cognitive and Behavioral Changes. The measure demonstrated effective items, high internal consistency, and satisfactory predictive, convergent, and discriminant validity. Conclusions: The DESV-Q is a purpose-specific instrument that could be used in future research to elucidate people's attributions for alcohol-involved sexual aggression and victimization.     

Social drinkers underestimate the additive impairing effects of alcohol and visual degradation on behavioral functioning

Rationale Studies have shown that social drinkers are poor estimators of alcohol-induced impairment. Underestimates of blood alcohol concentration and other indices of intoxication are associated with decisions to perform risky behaviors, such as operating a motor vehicle. It is possible that self-evaluations of impaired functioning under alcohol might be particularly compromised in the presence of other sources of impairment. A common source of impairment that co-occurs with alcohol is visual degradation.Objectives The present study compared actual and self-evaluated impairment in response to four conditions (0.65 g/kg alcohol, degradation of task-relevant stimuli, alcohol plus visual degradation, and no-treatment control) to determine whether social drinkers would perceive an increase in impairment from the combined treatments.Methods Actual psychomotor impairment was measured in 16 social drinkers (eight men) by a pursuit rotor task and their self-evaluations of this impairment were obtained on a rating scale.Results Alcohol and visual degradation impaired participants actual performance to a similar degree and, in combination, the impairing effects were additive. Participants self-evaluation ratings showed that they underestimated the additive impairment produced by the combination of alcohol and visual degradation.Conclusions The findings suggest that social drinkers might be unable to appreciate an increase in behavioral impairment when alcohol is consumed in the context of another impairing influence.     

The consequences of providing drinkers with blood alcohol concentration information on assessments of alcohol impairment and drunk-driving risk.

OBJECTIVE: We examined the effect of providing drinkers with blood alcohol concentration (BAC) information on subjective assessments of alcohol impairment and drunk-driving risk. METHOD: We sampled 959 drinking participants from a natural drinking environment and asked them to self-administer a personal saliva-based alcohol test. Participants then were asked to rate their alcohol impairment and to indicate whether they could drive legally under one of four BAC feedback conditions (assigned at random): (1) control condition (no BAC feedback provided before the ratings); (2) categorical BAC information (low, high, and highest risk) from the saliva test; (3) categorical BAC information corroborated by a calibrated police breath alcohol analyzer; and (4) precise (three-digit) BAC information from the breath alcohol analyzer. RESULTS: Both control participants and participants who received precise BAC feedback gave subjective impairment ratings that correlated with actual BACs. For participants who received categorical BAC information from the saliva test, subjective impairment did not correlate with the actual BAC. Providing drinkers with BAC information, however, did help them predict more accurately if their BAC was higher than the legal BAC driving limit. CONCLUSIONS: Although BAC information can influence drinkers' assessments of alcohol impairment and drunk-driving risk, there is no strong evidence that personal saliva-based alcohol tests are particularly useful.     

Subjective and Neural Responses to Intravenous Alcohol in Young Adults with Light and Heavy Drinking Patterns

Heavy alcohol consumption during young adulthood is a risk factor for the development of serious alcohol use disorders. Research has shown that individual differences in subjective responses to alcohol may affect individuals'' vulnerability to developing alcoholism. Studies comparing the subjective and objective response to alcohol between light and heavy drinkers (HDs), however, have yielded inconsistent results, and neural responses to alcohol in these groups have not been characterized. We performed a double-blind, placebo-controlled, randomized crossover alcohol challenge study comparing functional magnetic resonance imaging and subjective response to intravenously administered 6% v/v ethanol to a target blood alcohol concentration of 0.08% or placebo between HDs and social drinkers (SDs). During the imaging, we presented emotional cues in order to measure how emotion modulated the effects of alcohol on the brain''s reward circuitry. We found that, at equivalent blood alcohol concentrations, HDs reported lower subjective alcohol effects than SDs. Alcohol significantly activated the nucleus accumbens in SDs, but not in HDs. Self-reported ratings of intoxication correlated with striatal activation, suggesting that activation may reflect subjective experience of intoxication. Fearful faces significantly activated the amygdala in the SDs only, and this activation was attenuated by alcohol. This study shows that HDs not only experience reduced subjective effects of alcohol, but also demonstrate a blunted response to alcohol in the brain''s reward system. Our findings indicate that reduced subjective and neural response to alcohol in HDs may be suggestive of either the development of tolerance to alcohol, or of pre-existing decreased sensitivity to alcohol''s effects.     

Effects of family drinking history and expectancies on responses to alcohol in men

The effects of family drinking history and expectancies on responses to alcohol were studied in men nonproblem drinkers aged 19-30. A total of 24 subjects who reported a history of parental alcoholism (FH+) were compared with matched controls who did not have such a family history (FH-) on their responses to drinking either a placebo beverage, a low dose of alcohol or a high dose of alcohol. Despite comparable levels of tolerance and blood alcohol levels (BALs), FH- subjects reported higher levels of intoxication, behavioral impairment, anesthesia and central stimulation than FH+ subjects, regardless of the dose consumed. In contrast, FH+ subjects did more poorly on a timed motor task. There were no significant differences between the two groups on their self-reported beliefs about the effects of alcohol. However, multiple-regression analyses showed that BAL accounted for a greater percentage of the variance in the self-report data of FH- subjects, whereas expectancies were more predictive for the FH+ subjects. The results suggest that FH+ subjects did not base their evaluations of the effects of alcohol as closely on the internal and external consequences of intoxication. This finding is discussed as being one component of their heightened risk for developing alcoholism.     

In the company of others: social factors alter acute alcohol effects

Rationale

Alcohol is usually consumed in social contexts. However, the drug has been studied mainly under socially isolated conditions, and our understanding of how social setting affects response to alcohol is limited.

Objectives

The current study compared the subjective, physiological, and behavioral effects of a moderate dose of alcohol in moderate social drinkers who were tested in either a social or an isolated context and in the presence of others who had or had not consumed alcohol.

Methods

Healthy men and women were randomly assigned to either a social group tested in pairs (SOC; N?=?24), or an isolated group tested individually (ISO; N?=?20). They participated in four sessions, in which they received oral alcohol (0.8 g/kg) or placebo on two sessions each, in quasi-randomized order under double-blind conditions. In the SOC condition, the drug conditions of the co-participants were varied systematically: on two sessions, both participants received the same substance (placebo or alcohol) and on the other two sessions one received alcohol while the other received placebo. Cardiovascular measures, breath alcohol levels, and mood were assessed at regular intervals, and measures of social interaction were obtained in the SOC group.

Results

Alcohol produced greater effects on certain subjective measures in the SOC condition compared with the ISO condition, including feelings of intoxication and stimulation, but not on other measures such as feeling sedated or high, or on cardiovascular measures. Within the SOC condition, participants rated themselves as more intoxicated when their partner received alcohol, and paired subjects interacted more when at least one participant received alcohol.

Conclusions

The presence of others enhances some of the subjective and behavioral effects of alcohol, especially the presence of another intoxicated individual. This enhancement of alcohol effects may explain, in part, why it is used in a social context.     

Alcohol expectancies and social deficits relating to problem drinking among college students

Standardized questionnaires were administered to 116 male and female undergraduates to examine how social deficits and alcohol expectancies relate to alcohol use. Participants were classified as either problem or nonproblem drinkers based on the Rutgers Collegiate Substance Abuse Screening Test. Problem drinkers reported experiencing social anxiety, shyness, and lower self-esteem to a greater extent than nonproblem drinkers. Problem drinkers also held more positive alcohol expectancies than nonproblem drinkers. Contrary to our hypotheses, however, particular types of alcohol expectancies did not interact with specific areas of social functioning to influence problem drinking. Overall, these findings suggest that problem drinkers have positive expectations about the immediate effects of alcohol consumption even though drinking is linked to long-term impairment in social functioning.     

A cognitive model for the intergenerational transference of alcohol use behavior

A family history of alcoholism has shown to be one of the greatest consistent risk factors in the intergenerational transference of alcohol problems. Whereas a large number of studies have attempted to identify the processes responsible for this interfamilial transfer, the mechanisms remain unclear. Family, twin and adoption studies, and environmental theories have resulted in a number of unanswered questions regarding the extent that these factors influence the transmission of alcohol behavior. Recently, cognitive theories have suggested that the observation of parental drinking habits contributes to the child's beliefs and expectations of alcohol's effects. A hypothesised cognitive model will be proposed suggesting that the mechanism for the transference of particular drinking styles from parent to offspring may be further explained by the transference of alcohol cognitions, in particular, alcohol expectancies and drinking refusal self-efficacy. This review focuses on research of bio/psycho/social factors that perpetuate alcohol misuse across generations, and will delineate the proposed cognitive mechanisms for the interfamilial transference of alcohol problems and discuss the implications of the proposed model.     

Acute and residual effects of alcohol and marijuana,alone and in combination,on mood and performance

The duration of behavioral impairment after marijuana smoking remains a matter of some debate. Alcohol and marijuana are frequently used together, but there has been little study of the effects of this drug combination on mood and behavior the day after use. The present study was designed to address these issues. Fourteen male and female subjects were each studied under four conditions: alcohol alone, marijuana alone, alcohol and marijuana in combination, and no active treatment. Mood and performance assessments were made during acute intoxication and twice the following day (morning and mid-afternoon). Acutely, each drug alone produced moderate levels of subjective intoxication and some degree of behavioral impairment. The drug combination produced the greatest level of impairment on most tasks and strong overall subjective ratings. There were few significant interactions between the two drugs, indicating that their effects tended to be additive. Only weak evidence was obtained for subjective or behavioral effects the day after active drug treatments, although consistent time-of-day effects (morning versus afternoon) were observed on several subjective and behavioral measures. In sum, this study provided little evidence that moderate doses of alcohol and marijuana, consumed either alone or in combination, produce behavioral or subjective impairment the following day.     

Alcohol expectancies and social anxiety in male and female undergraduates

Recent studies have demonstrated that alcohol expectancies co-vary with some measures of trait anxiety. As part of a college drinking survey with 606 respondents (75.8%) evenly distributed by sex, this study tests further whether social anxiety predicts the expectancies of tension reduction, increased social assertiveness, and social/physical pleasure. In addition, the study examines whether sex, social anxiety, and alcohol consumption interact to predict alcohol expectancies. MANOVA analysis demonstrated that social anxiety significantly predicts the expectancies of tension reduction and increased social assertiveness but not the expectancy of social/physical pleasure. No interaction effects were found among sex, social anxiety, and consumption to predict expectancy levels. However, previous evidence that consumption levels (but not sex) predict expectancies was cross-validated. Findings are discussed within the context of a broader social learning model of alcohol use.     

Social anxiety and alcohol consumption: The role of alcohol expectancies and reward sensitivity

Although the relationship between social anxiety and alcohol consumption has been the subject of extensive exploration, previous studies have failed to draw consistent conclusions about the nature of this relationship.Gray [Gray, J.A. (1970). The psychophysiological basis of introversion–extraversion. Behaviour Research and Therapy, 8, 249–266] suggested that individuals who are sensitive to reward are likely to place themselves in potentially rewarding environments (e.g. pubs and clubs). As such these individuals will have a greater chance to experience and vicariously observe the effects of alcohol in these environments, leading to the formation and modification of alcohol expectancies. Consequently, reinforcement sensitivity theory and alcohol expectancies are inherently related, yet have remained disparate areas of research. In this study, a total of 454 young adults responded to a questionnaire assessing social anxiety, alcohol consumption, reward sensitivity and alcohol expectancies. Regression analyses revealed a positive relationship between reward sensitivity, expectations of tension reduction and increased confidence, and alcohol consumption. Expectations of tension reduction were observed to moderate the relationship between social anxiety and alcohol consumption. In addition, three-way relationships between reward sensitivity, alcohol expectancies and social anxiety were observed to predict alcohol consumption. Overall, these results suggest that both reward sensitivity and alcohol expectancies play a role in the relationship between social anxiety and alcohol consumption, and that inclusion of these constructs in further research may aid in further clarifying the mechanisms underlying comorbid social anxiety and alcohol abuse.     

Alcohol,expectancy and stress: Methodological concerns with the expectancy design

Recent research has indicated that many of the behavioral effects of alcohol consumption are largely due to covert expectancy effects. The purpose of this investigation was to assess the impact of alcohol and the expectancy of alcohol on physiological, subjective, and behavioral responses in a public speaking situation. Each of 28 male social drinkers was randomly assigned to one of four expectancy groups which controlled for the expectancies associated with the consumption of either an alcoholic or nonalcoholic beverage. After administration of the beverage, the subjects were informed that they would be asked to make a speech which would be videotaped for future evaluation. Following these instructions subjects listened to audiotaped materials designed to be stress enhancing, after which they made the videotape. No expectancy effect was found. Confidence in the beverage deception was discussed, as were the implications of the data in regard to excessive alcohol consumption in a stressful situation.     

Lack of tolerance to the disinhibiting effects of alcohol in heavy drinkers

Rationale

Alcohol tolerance is observed as a diminished response to a given dose as a function of repeated administrations of the drug. Research has consistently shown that heavier drinkers display reduced reactions to alcohol (i.e., tolerance) compared with lighter drinkers. However, the majority of this work has focused primarily on measures of motor performance, whereas the development of tolerance to alcohol's impairing effects on cognitive processes, such as inhibitory mechanisms of behavioral control, remains relatively unexplored.

Objective

The purpose of the present study was to examine the relationship between drinking habits and the degree to which alcohol affects drinkers' inhibitory control and motor coordination.

Methods

Fifty-two non-dependent drinkers reported their recent drinking patterns. Their inhibitory control and motor coordination were measured in response to placebo and 0.65?g/kg alcohol.

Results

Alcohol significantly impaired inhibitory control and motor coordination compared with placebo. Moreover, greater quantity and frequency of recent consumption predicted less alcohol impairment of motor coordination. However, there was no relationship between recent drinking habits and the degree of impairment of inhibitory control.

Conclusions

These findings suggest that tolerance to the disinhibiting effects of alcohol might not readily develop as a result of recent, heavy drinking.     

Application of the PTSD-alcohol expectancy questionnaire (P-AEQ) to sexually assaulted college women

Risk of alcohol use problems is an important clinical concern for women who have been sexually assaulted and experience PTSD symptoms. This study explored this risk by testing a factor structure of an alcohol expectancy questionnaire that assesses beliefs about alcohol's effects on posttraumatic stress symptoms (P-AEQ). Symptom-specific expectancy scores were then tested as predictors of alcohol consumption. Subjects were 96 female undergraduate women who reported being forced to have sex, 68 who experienced pressure to have sex, and 149 who denied any forced or pressured sex. Alternative factor models were tested using Confirmatory Factor Analysis. A four-factor model reflecting posttraumatic stress symptom domains (Intrusions, Avoidance, Arousal, and Numbing) was found. The numbing factor was correlated with drinking among assaulted women; however, no support was found for symptom-specific expectancies to moderate between assault and drinking. Findings supported a role for posttrauma symptom-specific alcohol expectancies as a potential link between sexual assault and alcohol consumption.     

Self-medication or social learning? A comparison of models to predict early adolescent drinking

The current study examined the effects of social anxiety, depressive symptoms, and alcohol expectancies of social behavior change on alcohol involvement to determine whether the self-medication and/or social learning models predicted drinking behavior in a sample of over 400 eighth grade students. Middle school students completed confidential surveys that assessed current alcohol use and expectancies as well as negative affectivity including social anxiety and depressive symptoms. Consistent with the self-medication hypothesis, depressive symptoms predicted more frequent and heavier alcohol use as well as solitary drinking. The social learning model was supported by a negative association between social anxiety and quantity/frequency of drinking and less drinking at parties, and a positive association between alcohol expectancies and all drinking outcomes. Additionally, social anxiety moderated the association between expectancies and alcohol use. These findings suggest that self-medication and social learning processes may both play a role in predicting early adolescent alcohol use and the contexts in which youths drink.     

Predictors of Frequency of Drinking to Cope in Socially Anxious Men and Women

Abstract

Objectives: Frequent drinking to relieve anxiety increases the risk of alcohol problems. It is hypothesized that the high rate of comorbidity of alcohol-use disorders and anxiety disorders may be due, in part, to the practice of self-medication with alcohol. Of interest to researchers and clinicians are individual variables that predict the practice of frequent drinking to cope in individuals with marked anxiety. The present pilot study was conducted to examine this issue in men and women with social anxiety. Methods: Twenty individuals with high social anxiety (11 women) were included in the investigation. All participants endorsed using alcohol to relieve social discomfort. Participants completed a standardized assessment battery and a study-specific questionnaire regarding the practice (and frequency) of drinking for anxiety relief in social situations. Regression analyses were conducted to examine variables that predicted frequency of drinking to cope, including severity of social anxiety, alcohol expectancies, and degree of anxiety relief afforded by alcohol. Results: Results suggest that individuals who experience alcohol as a powerful anxiolytic most frequently use alcohol to “self-medicate.” In addition, tension reduction expectancies also predicted more frequent drinking to cope, though only for men. Conclusions: The results of this investigation suggest that follow-up studies be conducted to specifically examine the degree of anxiety relief from alcohol, and tension reduction expectancies as potentially important variables that may help identify who is at greatest risk for developing alcohol problems in this at-risk group.     

Alcohol expectancies, social and environmental cues as determinants of drinking and perceived reinforcement.

Increasing evidence suggests that outcome expectancies and environmental cues interact to influence post-drinking behaviors. Using an experimental methodology in a simulated social drinking setting, this research tested the potential influence of expectations for the effects of drinking, environmental cues, and beverage content on ad lib consumption and post-drinking self-perception. Eighty-eight moderate to heavy-drinking males were randomly assigned to one of eight experimental conditions in which beverage content (alcohol or placebo), social environment (friendly or unfriendly), and physical environment (simulated bar or residence) were varied. Subjects were further divided into high and low groups on three outcome expectancy factors. Unaffected by environmental cues, beverage self-administration increased when subjects strongly expected behavioral impairment from drinking but received placebo beverage. Post-drinking reports of disinhibition increased in response to friendly social cues but were not affected by beverage content or amount. Results therefore suggest that individual's beliefs about the effects of drinking influence the amounts of beverage they consume, whereas social cues more greatly affect post-drinking self-perception.     

Family history of problem drinking among young male social drinkers: behavioral effects of alcohol

Two experiments examined the behavioral effect of alcohol on male social drinkers aged 19-25, who differed in their family histories of problem drinking--21 reported a problem drinker in their immediate family (FH+) and 22 had no such family history (FH-). These groups did not differ in age, weight or absolute alcohol per kg of body weight typically consumed on social occasions. After drinking absolute alcohol (0.83 ml/kg), subjects performed bead stringing and hand steadiness tasks when their blood alcohol levels (BALs) averaged 63 mg/dl on the rising and the declining limb of the BAL curve. The experiments consistently demonstrated that FH+ individuals displayed a greater degree of impairment on the tasks. One of the experiments also explored subjective ratings of the effects of alcohol at matching BALs and found no significant group differences. The greater behavioral sensitivity to alcohol of FH+ subjects and their apparent absence of a concomitant enhanced perception of its effects were discussed as a potential component of their higher risk of developing problem drinking.