Tag Archives: alcohol consumption

Do Self-Reports on Drinking Motives Reflect Actual Alcohol Consumption in Real-Life Scenarios?

Posted on December 12, 2012 by Becca| Leave a comment

 

What motivates someone to drink has been linked to the amount of alcohol one typically consumes.  Previously on The Academic Wino, a study was presented that showed people consuming alcohol for “positive” reasons (such as the taste or the health benefits of the wine) did not typically express problem drinking behaviors, whereas people consuming alcohol for “negative” reasons (such as reducing anxiety, coping with stress, or peer pressure) are much more likely to experience problem drinking behavior.

Some studies have shown that those that are motivated by internal factors, such as drinking to have fun or drinking to forget personal problems, are much more likely to drink more heavily than those that are motivated by external factors, such as drinking to be socialor drinking to fit in with the group.  The thinking is that those that are influenced by internal factors will tend to drink not only when

Philippe Mercier (circa 1689(1689)-1760) [Public domain or Public domain], via Wikimedia Commons

they are with other people, but also when they are all alone, whereas those that are influence by external factors will only tend to drink when in the company of a group of people.  To generalize, those influenced by external factors tend to be more moderate drinkers overall than heavy drinkers.

To date, nearly all of the studies focused on motivation for drinking have relied upon self-reporting by the participants themselves, a method by which is known to suffer from bias.  To be more specific, there could be errors in the self-reporting data due to forgetfulness of past events, as well as guilt or embarrassment by the participant in regards to how much they actually drink on a regular basis.

To combat this issue of bias in self-reporting, the study presented today combined self-reporting with a wine tasting experiment, in order to determine if drinking motives as reported by participants were able to predict the amount of alcohol consumed during the tasting sessions some time later or if the answers supplied by participants inaccurately represented their drinking habits in actual drinking situations.

Methods

Participants were recruited in the fall of 2010 from Lausanne University in Switzerland and were required to be between the ages of 18 and 25, have no significant health problems or history of substance abuse.

Participants filled out a 10 minute questionnaire that asked questions related to sociodemographics as well as alcohol consumption behavior questions.

A total of 123 subjects participated in all experiments during the study.

As an incentive to participate, subjects were entered into a drawing to win the equivalent of $600 USD, were given money to cover the cost of public transportation to the sessions, and were given a snack after each session.

There were a total of 3 data collection sessions: 1) the questionnaire; 2) a first wine tasting session; and 3) a second wine tasting session. There was a total of 1 month in between each session.

Participants were told that the wine tasting experiments were to determine the influence of human interactions on sensory experiences during the tasting.

Wine tasting sessions were held in an area designed to look like a comfortable bar.  Participants were asked to refrain from drinking any alcoholic beverages within 12 hours before each wine tasting session.

At the start of each tasting, a research assistant went over standard wine tasting protocol with participants.  Participants were each given a spit bucket as well as water.  Participants were told that they were not required to swallow the wines they tasted.

During the tasting sessions, participants were given 4 glasses with 110g of red wine.  The alcohol level of the wine was 13.5%, which translates to about 12g of alcohol per glass of wine.  Each tasting session lasted 25 minutes.

To determine the influence of social context on amount of alcohol consumed, the two tasting sessions were arranged so that either the participants were separated from one another to prevent any interaction or visual contact or they were arranged in groups of 4-8 participants with the ability to interact and be social.  In the group setting, discussions were moderated by the research assistant.  For each tasting session, men and women were kept separately from one another.  Each participant was randomly assigned to a tasting group; in order to (as the authors explained) avoid close friends participating in the same group together.

After the tasting sessions, the amount of wine remaining in the glass for each individual was measured, as well as how much wine was found in the spit buckets for each individual.  The amount of wine left in the glasses and in the spit buckets was subtracted from the original amount of wine presented to the participants, and converted to grams of pure alcohol.  This value represented the total amount of alcohol consumed per tasting session per individual participant.

By CDC [Public domain], via Wikimedia Commons

Drinking motives, alcohol use, and problem drinking behavior was analyzed and determined using participants’ responses on a questionnaire.

Drinking motive categories included: 1) enhancement (i.e. drinking to have fun); 2) coping (i.e. drinking to forget personal problems); 3) social (i.e. drinking to be social among peers); and 4) conformity (i.e. drinking to fit in with the group).

 

 

 

 

 

Results

  • 45.5% of participants were male, and 54.5% were female.
  • The mean age of participants was 21.9 years.
  • 17.1% of participants were found to be socially motivated.
    • 52.4% of the socially motivated participants were male and 47.6% were female.
  • 16.3% of participants were found to be enhancement motivated.
    • 55.0% of the enhancement motivated participants were male, and 45% were female.
  • 70.6% of the conformity motive participants were female, while 29.4% were male.
  • 54.5% of participants claimed they drank two or more times per week.
  • 60.2% of participants claimed they drank three or more drinks during a day that they are drinking.
  • 35.0% of participants claimed they had 6 or more drinks during a day that they are drinking.
  • Participants reporting high quantities of drinking or binge drinking tended to be motivated more by enhancement motives than those drinking for any other motive.
  • During the first wine tasting session, an average of 15.6g of alcohol per participant was consumed.
  • During the second wine tasting session, an average of 18.8g of alcohol per participant was consumed.
    • The tendency to drink more during the second session was most notable among participants drinking for coping reasons.
  • Drinking greater amounts of alcohol was associated with high levels of social motivation, as well as a low level of coping or conformity motivation.
  • Men reported drinking more frequently and binge drinking more often than women.
  • For both tasting sessions, men consumed 22.5g more alcohol than women (on average).
    • Men consumed 11g more alcohol than women during the first tasting session, and 11.4g more alcohol during the second tasting session.
    • Looking at each tasting session separately, there were no significant differences between the sexes in regards to alcohol consumption (though it was close).  Taking both tasting sessions together, men consumed significantly more alcohol than women.
  • Those participants starting in the group setting during the tasting sessions consumed 7.9g more alcohol than participants starting in the individual setting.
  • Those participants self-reporting as being motivated by enhancement reasons consumed significantly more alcohol than participants reporting other motivations for drinking.
  •  Those participants self-reporting as being motivated by conformity reasons consumed significantly less alcohol than participants reporting other motivations for drinking.
  • The self-reported motivation for drinking could not predict the amount of alcohol consumed during each tasting session individually, however, self-reported motivation for drinking could predict the total amount of alcohol consumed after both tasting sessions.
  • From the first tasting session to the second tasting session, coping motivated drinkers significantly increased their alcohol consumption.
  • From the first tasting session to the second tasting session, socially motivated drinkers significantly decreased their alcohol consumption.

Conclusions

According to the authors of this study, when taking the amounts of alcohol consumed from both tasting sessions together, the actual amounts of alcohol consumed was very highly correlated with the amounts of alcohol reported by the participants in the questionnaire.  In other words, according to these results, motives for drinking allow one to predict the amount of alcohol consumed by an individual in a particular setting.

The authors also stated that those than are motivated by internal reasons (i.e. drinking for enhancement or coping purposes) tend to take advantage of a drinking situation where alcohol is readily available and free.  The authors claim that this may be a result of their desire to attain the psychoactive effects of the alcohol itself in order to “maximize pleasurable sensations” or perhaps more readily forget their personal problems.  To explain the results of externally motivated participants, the authors surmised that they likely drank lower amounts of alcohol because they tend to be inconsistent in their drinking patterns, and perhaps since they did not know the other people in their tasting groups, they were less likely to drink more.

When looking at the tasting sessions individually, the authors noted that drinking motive could not predict the amount of alcohol consumed per session (particularly the first session).  They reason this result to be potentially due to the nature of the experimental design itself.  Perhaps since participants were not familiar with the tasting procedure they were asked to do, the location they were performing the tastings in, or the other participants they were paired up to taste with, they were uncomfortable with the situation and less likely to consume the

By che (che) [CC-BY-SA-2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons

same levels of alcohol they would have consumed if they were in a more comfortable and familiar environment.  This may explain why alcohol consumption increased during the tasting session, since at this point, the participants had a chance to get used to the situation and became more comfortable and familiar with the whole thing.

The authors noted some limitations with the study, including the sample size and the way participants actually felt about the wines they were drinking.  The study only included only 123 college students between the ages of 19 and 24, which is certainly not representative of the general population. Would older participants when placed in the same situations yield similar results? Or would there be significant differences in drinking motivation and alcohol consumption behavior across generations?

In regards to not testing how the participants felt about the wine they were consuming, I feel as though this could potentially have significant consequences on the overall results (or not…I’m not completely certain).  What if a significant proportion of participants don’t drink wine to begin with?  They then may not be consuming the amount of alcohol they normally would be under a given situation due to simply not liking beverage used in the study.  Perhaps they would drink even more if they had been handed fruity mixed drinks instead of red wine.  After all, studied do show that younger individuals drink more of these types of beverages than wine (in general) when compared to their older counterparts.

Overall, the results of this study confirm that self-reported drinking behavior is correlated with the actual amount of alcohol consumed during a wine tasting session.  I would be hesitant to say this with complete confidence, mainly based on the limitations I just discussed in the previous two paragraphs.  I think the results are interesting and certainly a good start, however, I think these limitations would need to be addressed before I am completely convinced these results to be accurate and reflective upon the general population.

What did you all think of this study? What would you like to have seen differently? Maybe I’m being too harsh regarding the limitations: do you think these limitations are insignificant to the results? Please feel free to comment!

Source: Kuntsche, E., and Kuendig, H. 2012. Beyond Self Reports: Drinking Motives Predict Grams of Consumed Alcohol in Wine-Tasting Sessions. Experimental and Clinical Psychopharmacology 20(4): 318-324.

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Women Prefer Wine and Liquor While Men Prefer Beer: Using an Implicit Measures Approach to Determine Consumer Behavior

Posted on October 22, 2012 by Becca| Leave a comment

Often when we see a study examining alcohol preferences and habits in people, we cannot be certain if the results are based on what the participants want to report due to potential guilt or embarrassment, or if the results are actually based on fact.  Survey-type research often runs the risk of experiencing this type of variation, which may not actually reflect what the individual or group of individuals prefers or how they behave in real world situations.

One way to work around the survey method in order to obtain a potentially more accurate presentation of consumer preference and behavior is using what is called “implicit measures”.   What this means is that the strength of an

Photo by jenni from the block: http://farm9.staticflickr.com/8434/7827785878_34859830a8.jpg

association (i.e. how strongly one associates or attaches oneself to a particular stimuli such as a specific type of alcohol) is inferred by the behavior of an individual as opposed to simply asking the individual how they feel about that particular stimuli.  Using implicit measures allows for capturing information that is beyond the conscious control of the individual, theoretically giving a more accurate representation of their preferences and consumption behaviors.

The short communication (i.e. quick study) presented today aimed to evaluate using implicit measures to determine how gender and drinker status (i.e. how much and how often one drinks) relates to selection stimuli (in this case, type of alcohol).  The implicit measures test used in this study is the Implicit Association Test (IAT).  This test uses picture or words to represent a single type of alcohol or picture or words to represent different types of alcohol.  According to the authors, this type of methodology could provide more accurate answers and ensure that the choice made actually reflects the true behavior of the consumer compared to survey methods or other methods that may be inaccurate and inconsistent.

Note: this study is a test of methods.

Methods

300 undergraduates (136 male, 164 female) between the ages of 18 and 25 (mean = 20.47) participated in this study.  They were recruited by email, and were told that they would be participating in a research study about cognitive processes and alcohol.

  • 57% identified themselves as white/Caucasian;
  • 30% Asian;
  • 9% multiracial;
  • 4% as black/African American, American Indian/Alaska Native, Native Hawaiian/other Pacific Islander, unknown, or declined answer.

During the IAT test, classification of preference should be faster when the

Photo by batrax: http://farm1.staticflickr.com/24/92549990_37387f7ca0.jpg

pairing of the target and attribute categories match the individual’s personal associations in their memories.  Two separate IAT tests were used:  alcohol approach (approach or avoid) and alcohol excitement (excite or depress).  A higher IAT score indicates a stronger relationship between alcohol and approach than alcohol and avoid, and between alcohol and excite than alcohol and depress.  In other words, a higher score indicates the individual would consume the alcohol and not avoid drinking it, and that the individual is excited about drinking a particular type of alcohol and not indifferent or “depressed” about drinking another type.

During the test, participants selected four images of alcoholic beverages out of 15.  Each image contained 3 different examples of the alcohol they were representing (i.e. 3 different types of beer or 3 different types of wine, etc).  They were asked to choose the images that corresponded to the type of alcohol they drink most often, and if they were classified as “non-drinkers”, they would select the image that corresponded to the type of alcohol that was offered to them most often.

Quantity of consumption at one time and frequency over the past 30 days were also measured.

Results

  • Women chose more wine and liquor than men.
  • Men chose more beer than women.
  • Those considered heavy episodic drinkers (i.e. binge drinkers) chose more beer than those that were not binge drinkers.
  • Binge drinkers chose less wine than those that were not binge drinkers.
  • Binge drinkers chose more liquor than those that were not binge drinkers.
  • Female non-drinkers were more likely to choose iced malt beverages than female binge drinkers.
  • Those who consumed higher amounts of alcohol had higher IAT scores than other consumers
    • In other words, they associated more closely with “alcohol and approach” than “alcohol and avoid” and more closely with “alcohol and excite” than “alcohol and depress”.
    • Non-drinkers had significantly lower IAT scores than binge drinkers and those consuming alcohol more moderately.

Conclusions

In general, the results of this study are consistent with other studies examining the drinking habits of college students.  Males preferred more beer than females, and females preferred more wine and/or liquor than males.  In regards to the preference of those who consumed a heavy amount of alcohol at one time, those participants preferred more beer and liquor, and not wine.  Finally, females that do not drink alcohol and those that do not drink heavily at one time preferred iced malt beverages more than the other participants.

Results from the IAT test suggest that alcohol associations (i.e. “approach or

Photo by Rennette Stowe: http://farm9.staticflickr.com/8308/7847608288_5b02fcc912.jpg

avoid” or “excite or depress”) are sensitive to differences in the amount of alcohol consumed and not to the particular type of beverage selected.  In other words, IAT test scores were significantly higher for those that consumed heavily during a drinking episode than for those that do not consume heavily at one time or that don’t drink at all.

The authors suggest that due to these results, research examining alcohol preferences among individuals or groups should use the Implicit Association Test, which would help decrease variability associated with survey-type methods that can be complicated by lying or stretching of the truth due to guilt or embarrassment.

One problem with this study is that it only includes undergraduate students; therefore the results may or may not reflect what the entire population as a whole represents.  The study also did not include other types of alcohol such as alcoholic energy drinks, even though these types of beverages are popular among college-aged students.

Ultimately, the authors claimed that the results of this study indicate that implicit measures may be a more appropriate and more accurate methodology for measure actual preferences of alcohol consumers than traditional survey methods.

I would like to have seen this study coupled with a survey method, to compare the results from the survey directly to the results of the implicit measures test.  The authors say that the implicit measures method would provide more accurate results in regards to actual alcohol consumption behavior, however, they do not describe or compare what the participants responses would have been if they were just answering the questions directly on a survey.  If they did do this, it wasn’t made clear in the paper.

What do you all think about using implicit measures methods for determining consumer behavior?  Have you ever filled out a survey asking for alcohol consumption habits?  Did you stretch the truth a little, or were you completely honest?  Please feel free to leave your comments!

Source: Lindgren, K.P., Westgate, E.C., Kilmer, J.R., Kaysen, D., and Teachman, B.A. 2012. Pick your poison: Stimuli selection in alcohol-related implicit measures. Addictive Behaviors 37: 990-993.

 

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Does Wine Consumption Really Lower Mortality Risk in Adults?: Evidence for the Contrary

Posted on May 17, 2012 by Becca| Leave a comment

There is a lot of evidence in the literature that claims moderate alcohol consumption is associated with reduced mortality in adults.  For example, studies have shown that wine consumption in particular reduces cardiac mortality, as well as other beneficial effects.  One hypothesis is that because wine has such unique protective properties, it is this beverage that provides the reduced mortality in adults, and not all types of alcoholic beverages.  Though many studies have shown these types of results, many are still concerned that these results are too tightly linked with several confounding factors, including socioeconomic and lifestyle factors.

http://images.sciencedaily.com/2010/08/100824161432-large.jpg

Preferences for wine has been shown to be highly associated with a higher socioeconomic status, a healthier lifestyle, and better health statuses in general.  One study controlling for many of these factors found that associations between reduced mortality rates and reduced risk of heart attack in older adults were not correlated with the type of alcohol that was consumed. 

So, does wine consumption really reduce mortality in adults?  Or are the results of many of the studies out there inaccurate due to uncontrolled confounding factors?

The goal of the study presented today was to answer these very questions.  What is the relationship between the level of wine consumption and the mortality rate in adults when controlling for confounding factors?  Several questions were asked in this study: 1) Is the mortality advantage of moderate alcohol consumption retained in both high-wine consumption individuals and low-wine consumption individuals?; 2) Are there significant confounding factors associated with a high level of wine consumption?; 3) Are controlling for confounding factors, is there a mortality advantage of high-wine consumption versus low-wine consumption?; and finally 4) Is there a mortality advantage associated with the level of wine consumption independent of the confounding factors?

Methods

This study was a part of a larger study examining late-life patterns of alcohol consumption and drinking problems, and stress and coping processes among late-middle aged adults.  At baseline, participants were between 55 and 65 years old and who had outpatient contact with a health care facility within the last 3 years.  Lifetime nondrinkers were excluded from the study.  All data were collected by self-reporting.

802 adults participated in the study, and were broken down into three different groups: abstainers, high-wine consumption moderate drinkers, and low-wine consumption moderate drinkers.  Information was collected on alcohol consumption, sociodemographic factors, health behaviors, health problems, and physical activity.

The following factors were assessed for alcohol consumption:  average daily ethanol consumption, quantity of alcohol consumed, frequency of alcohol consumed, and type of alcohol consumed.  From the information gathered, quantity-frequency values were calculated in order to create participant indices of average daily ethanol consumption for each beverage type.  By summing this average daily ethanol consumption index for each beverage type, a composite index of the participants’ overall average daily ethanol consumption was calculated.

Abstainers were identified as those who had consumed no alcohol in the past year.  Moderate drinkers were identified as those who consumed from one to less than three drinks per day in the last month.  There were a total of 345 abstainers and 560 moderate drinkers in total.

Among the moderate drinkers, the level of wine consumption was determined.  Low-wine consumers were the moderate drinkers who consumed less than or equal to one third of their daily ethanol consumption from wine.  High-wine consumers were the moderate drinkers who consumed two thirds or more of their daily ethanol consumption from wine.  There were a total of 281 low-wine consumers and 176 high-wine consumers.

Sociodemographic factors measured were: age, gender, socioeconomic status, total annual family income, years of education, and marital status.

Health problems measured as a choice of 9 different problems (participants could select as few or as many that applied to them) that were physician-diagnosed medical conditions within the past year including: cancer, diabetes, heart problems, stroke, high blood pressure, anemia, bronchitis, kidney problems, and ulcers.  Participants were also asked to choose from 7 different physical problems that were applicable to them within the last year, including: pain in the heart or tightness/heaviness in the chest, trouble breathing or shortness of breath, constant coughing or frequent heavy chest colds, frequent cramps in the leg, swollen ankles, getting very tired in a short time, and trouble climbing stairs or getting outdoors.

The following health behaviors were measured: tobacco smoking and physical activity.  For physical activity, participants were asked to choose their level of activity based on four scenarios: swimming or tennis with friends, swimming or tennis with family, long hikes or walks with friends, or long hikes or walks with family.

The outcome variable for this study was death.  At the end of the 20-year follow-up for this study, 435 participants out of 802 had died.

Results

  •        Not taking any confounding factors into consideration, the mortality rate was highest for abstainers (69%), intermediate among low-wine consumers (50%), and lowest for the high-wine consumers (32%).
  •       After controlling for the covariates (a.k.a. confounding factors described above), both high-wine and low-wine consumption moderate drinkers showed reduced mortality risks compared with abstainers.

What about the level of wine consumption?

  •       Level of wine consumption was significantly associated with 5 out of 6 covariates, and trending with the 6th, physical activity.
  •       Compared to high-wine consumers, low-wine consumers tended to be older, male, more reported health problems, tobacco smokers, lower on the socioeconomic scale, and reported in engaging in less physical activity.

Is there a mortality advantage associated with level of wine consumption among moderate drinkers?

  •       WITHOUT controlling for demographic and lifestyle confounding factors, but controlling for average daily ethanol consumption, low wine consumption among moderate drinkers was associated with a higher risk of mortality (85%) compared to high wine consumption.
  •       Mortality risk did not differ between men and women.

What about the mortality advantage associated with level of wine consumption among moderate drinkers after controlling for all confounding factors?

  •       After controlling for all of the covariates, including average daily ethanol consumption, theinitial difference in mortality between high-wine consumers and low-wine consumers was no longer significant.
  •       Mortality risk did not differ between men and women, even after controlling for all confounding factors.

Conclusions

After controlling for confounding factors, which is frequently not done in related studies, the results of this study found that the mortality advantage of moderate alcohol consumers over those abstaining from alcohol does not appear to be based solely on their consumption of wine.  In other words, there is no difference in mortality rate between wine drinkers and other alcoholic beverage drinkers when controlling for all confounding factors. 

The study found that there is strong evidence that confounding sociodemographic, behavioral, and health factors were highly associated with wine consumption.  In other words, a lower mortality rate for wine drinkers doesn’t necessarily mean it’s because of the wine they are consuming, but could be instead due to one or many of the sociodemographic, health, and other factors that are highly correlated with wine consumption. 

The authors of this study did address some limitations to their methods, which I will briefly summarize here.  First of all, these results are not from experimental findings and do not show evidence of causality.  Second, these results are based off self-reports, which may or may not be completely accurate (though many studies have shown that they are).  Third, the measure of physical activity was extremely limited and therefore the results reported may not be accurate to what physical activity was actually performed in real life for each participant. 

Next, the study did not differentiate between red and white wine, though in one study, it was shown that mortality risk was identical between red and white wine.  Next, the study did not give any information on patterns of hazardous drinking (i.e. binge drinking) if they occurred in the life of the participant.  Next, the majority of the participants were white, so these results may not be generalizable to the general public.  Finally, the study did not take into consideration any changes in alcohol consumption patterns over the 20 year period.

Overall, this study found that the failure of many studies to control for confounding factors, such as sociodemographics and health behaviors, has led to the widely accepted notion that there is a mortality advantage for older adults who consume wine instead of other alcoholic beverages.  However, what this study found is that many sociodemographic, behavioral, and health status are linked to both the level of wine consumption and to increased mortality, therefore the results of other studies not controlling for these variables are inaccurate.  So, after controlling for all of these confounding factors, the benefit of lower mortality associated with moderate wine consumption is eliminated.  Note: wine consumption DOES lower mortality risk compared to those that abstain from alcohol all together, but this study shows that it’s nothing special about wine that’s lower that risk, but perhaps the ethanol itself.

I’d love to hear what you all think of the results and implications of this study! Please feel free to comment below (no html tags, please).

Source: Holahan, C.J., Schutte, K.K., Brennan, P.L., North, R.J., Holahan, C.K., Moos, B.S., and Moos, R.H. 2012. Wine Consumption and 20-Year Mortality Among Late-Life Moderate Drinkers.  Journal of Studies on Alcohol and Drugs 73(1): 80-88.



I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

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Environmental Context Determines Self-Administered Alcohol Consumption Rates in Rats

Posted on March 13, 2012 by Becca| Leave a comment

Clinical research indicates that environmental context plays a very important role in altering individual responsiveness to addictive drugs.  For example, traumatic life experiences have been shown to be associated with the development of a drug addiction, or a relapse back to a former drug addiction.  This type of environmental influence on drug self-administration has also been seen in laboratory animals, such as rats.  Previous studies have found that non-resident rats (rats transferred to a separate chamber different from the one they were living in) self-administered higher levels of cocaine and amphetamines than resident rats that were presented with the drugs in their chamber of residence.  Conversely, the same study found that the opposite was found for heroin, where resident rats self-administered higher levels of the drug than non-resident rats.  Based on these results, it is suggested that environmental context and the drug type play important roles in self-administration in the rat model.

http://deerfieldranch.com/Linkimages/rats2.jpg

 

These differing responses between resident and non-resident rats and their self-administration rates of different types of drugs may, according to researchers, reflect an influence of contextual stimuli on the evaluation of the drug reward.  More specifically, researchers speculate that the environmental setting provides an ecological background against which drugs are rated as more adaptive or less adaptive.  What this means in plain English is that the sedative/depressive effects of heroin (or other depressants) are more suitable for a safe at-home environment, whereas activating/stimulating effects of cocaine (or other stimulants) are more suitable in unfamiliar, exciting environments.

For the current study presented today, the authors built upon this previous knowledge of self-administration of various drugs in different environmental contexts in the rat model, and expanded it to include alcohol.  Simply put, this study aimed to evaluate the oral self-administration of alcohol in resident and non-resident rats.  The authors predicted that alcohol self-administration in rats should be similar to heroin administration in rats, as both as depressants that display very similar symptoms in the consumer.  Specifically, the authors predicted that self-administration of alcohol would be higher in resident rats than non-resident rats.

Methods

167 male Sprague-Dawley rats between the weights of 220 and 240 grams were used for this study.  They were housed and tested in a single temperature and humidity controlled room, with continual access to food and water, except during the experimental sessions, and were kept under a 14 hour dark and 10 hour light cycle.  Rats were housed individually, and randomly assigned as resident or non-resident.

Experiment 1

Goal: To measure the intake of different solutions of alcohol in resident and non-resident rats. 

There were 12 groups of rats tested for 14 consecutive sessions.  Sessions lasted 3 hours each and took place during the dark cycle between 12pm and 3pm.  At the start of each session, food was removed, and then replaced immediately after the session ended.  Alcohol solutions were prepared fresh and at room temperature.  Bottles of solution were weighed before and after each session.

Baseline Sessions: One week after arriving at the facility, non-resident rats underwent 3 sessions to measure baseline water intake in their home cages (to compare when in non-resident cages)

First Baseline Session: Non-resident rats were given the alcohol test solution in their home cages to measure their baseline intake (to compare when in non-resident cages).  Three groups of rats received three ethanol solutions using 95% ethanol diluted with tap water: 2.5%v/v, 5%v/v, and 10%v/v.  Three other groups of rats were given a commercial white wine (Castellino, 11% alcohol by volume) diluted with tap water to produce the same levels of alcohol as the ethanol solutions: 2.5%v/v, 5%v/v, and 10%v/v. 

One Bottle Test Sessions:  Immediately before the experiment, non-resident rats were transferred into the testing chamber.  One bottle containing the same alcohol solution as the baseline session was provided to each rat.  At the end of each session, non-resident rats were returned to their home cages.

Two Bottle Test Sessions:  These sessions were nearly identical to the one bottle sessions, however during these sessions, two bottles of water were provided to each rat (choice), with one containing the alcohol test solution, and the other containing water.

Procedures for Resident Rats:  The procedures for resident rats were nearly identical to those for the non-resident rats, except that resident rats were tested in their home cage and were not transferred into any other cages throughout the experiment.  There was the same number of groups of resident rats as there were non-resident rats.

Experiment 2

Goal:  After analyzing Experiment 1, the researchers found that there were significant differences between the resident rat groups and the non-resident rat groups.  Therefore, the goal of Experiment 2 was to determine if these groups also differed in their intake of water.

Procedures for Experiment 2 were almost identical to the procedures for Experiment 1, except that the alcohol test solution was replaced by water.

Experiment 3

Goal:  The goal of Experiment 3 was to determine if there were any differences between resident and non-resident rats in the intake of a saccharine-quinine solution.

This was the goal of Experiment 3 since research has shown that there is a relationship between the preference for ethanol and a preference for bitter-sweet solutions in the rat model.  Some studies suggest that saccharine-quinine solutions more approximately reflect the bitter-sweet taste of alcohol solutions.

The procedures of Experiment 3 were nearly identical to the procedures in Experiments 1 and 2, except during this experiment, the alcohol (or water) solution was replaced by a saccharin-quinine solution.

For All Experiments

Each bottle that contained test solutions or water was checked repeatedly for any dripping.  For 7 days in a row, each bottle was weighed before being placed in a cage, and again after the 3 hour experimental session.  The average differences between the weights of the bottles were subtracted from the raw data.  Intake data was corrected by body weight, which was measured twice per week.  Intake of pure ethanol in Experiment 1 was calculated after correcting for concentration and relative density.

Results

Experiment 1

  •       There were no significant differences in body weights at the beginning of the experiment between resident and non-resident rats.
  •       All groups increased body weight throughout the duration of the experiment.
  •       Weight gain was significantly greater in the resident group than the non-resident group.

o   This was expected, as alcohol intake was higher in the resident group than the non-resident group.

§  Weight gain x environment interactions were not quite significant (approaching significance).  This means weight gain was similar between resident and non-resident rats.

§  There were no other significant interactions.

  •       During the 1 bottle test, alcohol intake was a function of environmental context, with no significant differences in the baseline intake between groups.
  •       Alcohol intake was significantly greater in the resident group than in the non-resident group.
  •       Alcohol intake was a function of concentration, though there was no environment x concentration interaction.
  •       Differences between resident and non-resident groups appeared to be greatest at the 5% concentration (up to 2 times greater).
  •       There was a significant effect of session, though no significant interactions with session and environment, session and concentration, or session and test solution.

o   As sessions wore on, resident rats greatly increased their alcohol intake, whereas non-resident rats greatly reduced their alcohol intake.

  •       There were no differences between ethanol solution intake and wine solution intake.
  •       For the 2 bottle tests, preference for alcohol over water was a function of both the environment and the concentration.

o   Intake of alcohol solutions relative to intake of water was greater in the resident rat groups than the non-resident rat groups.

§  This was due to a preference for alcohol over water in the resident rat group.

  •       The effect of environment was greatest at 5% alcohol concentrations.

o   Alcohol was preferred to water at concentrations of 2.5% and 5%.

o   Water was preferred to alcohol at the 10% concentration.

Experiment 2

  •       There were no significant differences between resident and non-resident rats in the intake of water at baseline or the entirety of the experiment, nor were there any significant interactions between any of the other variables.

Experiment 3

  •       There was no effect of environment on saccharin-quinine intake between resident and non-resident rats.

o   Resident and non-resident rats differed when non-resident rats were transferred into another cage during the first session of the one bottle test.

o   There was a significant effect of session, but not a significant effect of environment, and nor were there any significant interactions between the two.

  •       During the 2 bottle test sessions, there was a significant effect of choice, but not of environment, and there was only one significant interaction between them (the three-way choice x environment x session interaction).

Conclusions

Based on the results of this study, the authors concluded that alcohol self-administration in the rat is influence by the environmental setting in which that alcohol is consumed.  Specifically, they found that alcohol intake was greater for those rats living in the experimental chambers than those rats temporarily moved into an experimental chamber while living in a completely separate chamber while not undergoing testing. 

As far as the type of alcohol is concerned, it didn’t seem to matter if the rats were consuming ethanol alone or wine.  In regards to the saccharin-quinine results, it appears as though this choice was influenced in a different manner than the alcohol solutions.  Resident rats increased their intake of the test solution during Experiments 1 and 3, while non-resident rates decreased their intake of the test solution during the experiments.  During later sessions of the experiment, this effect of changing intake preferences rapidly declined when it came to testing the saccharin-quinine solutions, but not the alcohol intake.  The authors suggest this means that when exposed to new tastes, the rats are a little cautious, but then this cautiousness wears off over time.

As the authors predicted, resident rats consumed greater amounts of alcohol than non-resident rats, which they attribute to the depressant characteristics of the drug and the results of previous studies with heroin.  While a stimulating drug, such as cocaine, would be more likely experienced as more suitable in a strange, exciting environment, a depressant such as heroin (or in this case, alcohol), would be more suitable for safe, comfortable environments such as the home.

Overall, the authors of this study claim that based on these results, this paper shows at the preclinical level that setting or environment plays a very important role for the self-administration of alcohol.  These results seem to complement the one survey study of humans that concluded that there was a clear preference for heavy drinkers to consume larger amounts of alcohol in the comfort of their own home.  These results could have many implications in the health and psychological fields.

I’d love to hear what you all think!  Please feel free to comment below!

Source: Testa, A., Nencini, P., and Badiani, A. 2011. The role of setting in the self-administration of alcohol in the rat. Psychopharmacology 215: 749-760.

DOI: 10.1007/s00213-011-2176-9
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

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