Ethologically-based animal models of anxiety disorders.

The concept of moderate consumption of ethanol (beverage alcohol) has evolved over time from considering this level of intake to be nonintoxicating and noninjurious, to encompassing levels defined as "statistically" normal in particular populations, and the public health-driven concepts that define moderate drinking as the level corresponding to the lowest overall rate of morbidity or mortality in a population. The various approaches to defining moderate consumption of ethanol provide for a range of intakes that can result in blood ethanol concentrations ranging from 5 to 6 mg/dl, to levels of over 90 mg/dl (i.e., approximately 20 mM). This review summarizes available information regarding the effects of moderate consumption of ethanol on the adult and the developing nervous systems. The metabolism of ethanol in the human is reviewed to allow for proper appreciation of the important variables that interact to influence the level of exposure of the brain to ethanol once ethanol is orally consumed. At the neurochemical level, the moderate consumption of ethanol selectively affects the function of GABA, glutamatergic, serotonergic, dopaminergic, cholinergic, and opioid neuronal systems. Ethanol can affect these systems directly, and/or the interactions between and among these systems become important in the expression of ethanol's actions. The behavioral consequences of ethanol's actions on brain neurochemistry, and the neurochemical effects themselves, are very much dose- and time-related, and the collage of ethanol's actions can change significantly even on the rising and falling phases of the blood ethanol curve. The behavioral effects of moderate ethanol intake can encompass events that the human or other animal can perceive as reinforcing through either positive (e.g., pleasurable, activating) or negative (e.g., anxiolysis, stress reduction) reinforcement mechanisms. Genetic factors and gender play an important role in the metabolism and behavioral actions of ethanol, and doses of ethanol producing pleasurable feelings, activation, and reduction of anxiety in some humans/animals can have aversive, sedative, or no effect in others. Research on the cognitive effects of acute and chronic moderate intake of ethanol is reviewed, and although a number of studies have noted a measurable diminution in neuropsychologic parameters in habitual consumers of moderate amounts of ethanol, others have not found such changes. Recent studies have also noted some positive effects of moderate ethanol consumption on cognitive performance in the aging human. The moderate consumption of ethanol by pregnant women can have significant consequences on the developing nervous system of the fetus. Consumption of ethanol during pregnancy at levels considered to be in the moderate range can generate fetal alcohol effects (behavioral, cognitive anomalies) in the offspring. A number of factors--including gestational period, the periodicity of the mother's drinking, genetic factors, etc.--play important roles in determining the effect of ethanol on the developing central nervous system. A series of recommendations for future research endeavors, at all levels, is included with this review as part of the assessment of the effects of moderate ethanol consumption on the central nervous system.

Effects of Moderate Alcohol Consumption on the Central Nervous System

A self-awareness model of the causes and effects of alcohol consumption.

The literature on alcohol and stress in human subjects carried out since 1981 is reviewed. The review covers selected aspects of the interaction of alcohol and stress. (1) Most of the review focuses on the role of stress on alcohol ingestion. Retrospective research based on data from the Health and Nutrition Examination Survey indicated an increase in alcohol consumption with anxiety in certain groups of, as yet not well characterized, individuals. For example, although still insufficiently documented, stress does not appear to play a significant role in alcohol ingestion by women and the elderly. By contrast, stress does appear to play a role in the control of alcohol ingestion by adolescents. Prospective studies employing questionnaire-interview formats generally support an effect of stress on alcohol ingestion. However, studies employing male college aged social drinkers did not find a correlation between levels of stress and ingestion of alcohol. Alcoholics also differ in the reasons for drinking alcohol, but generally ingest alcohol to lessen anxiety/stress. It is clear that the Tension Reduction Hypothesis as originally postulated is no longer adequate. Many new models based on an interaction of alcohol and stress have been proposed to explain the control of alcohol consumption. Considering the multidimensionality of factors that appear to contribute to the control of alcohol ingestion, it is unlikely that a single model could possibly be relevant to alcohol ingestion under all conditions. More likely different models may be relevant to alcohol consumption under specific conditions, or for specific populations. (2) Alcohol has been reported to decrease anxiety in agoraphobics. The self-medication by agoraphobics may contribute significantly to their alcohol abuse. (3) Alcohol has also been reported to decrease tremor of the hands in stressed subjects as well as in patients with essential tremor. (4) Although a number of studies have employed electrodermal activity in studies aimed at the interaction of alcohol and stress, the results have been rather inconsistent. (5) The controversy on the purported beneficial effect of alcohol on the cardiovascular system persists. A number of studies have shown a J- or U-shaped relationship between alcohol ingestion and incidence of coronary heart disease. Alcohol may also influence stress-induced changes in blood pressure. Although a number of studies have demonstrated lower blood pressure in individuals ingesting less than two drinks per day compared with abstainers or heavy alcohol imbibers, the evidence is not conclusive. (6) It is not clear whether the interaction of alcohol and stress involves alterations in plasma catecholamines. Alcohol may lower elevated plasma catecholamines induced by some, but not all, stressors.

The inconsistencies in data in the reviewed literature most likely reflect some of the many variables associated with alcohol and stress research. These are also briefly reviewed and include subject-, drug- and stress-related variables.

Stress and alcohol interaction: an update of human research.

This article reviews the effects of alcohol on stress responses among social drinkers. Despite considerable research, the relationship between alcohol and stress has remained unclear. An appraisal-disruption model of alcohol's effects on stress responses is proposed, which attempts to integrate many divergent findings. According to this model, alcohol disrupts initial appraisal of stressful information by constraining the spread of activation of associated information previously established in long-term memory. The conditions under which such disruption is likely to occur are outlined. Evidence relevant to each of the model's propositions is considered. It is concluded that the appraisal-disruption model provides a framework for integrating many of the findings from past investigations. Theoretical issues pertinent to the model are addressed.

An appraisal-disruption model of alcohol's effects on stress responses in social drinkers.

The effects of alcohol on performance were investigated in 10 men and 10 women. On 4 psychomotor tasks minor gender-related effects of alcohol were found.

Effects of alcohol on psychomotor performance of men and women.

Ten male and 10 female nonalcoholic college students were given drinks having alcohol levels of 0, 0.5, 0.8, and 1.2 g/kg. They were then given four complex psychomotor tests, immediately before and after which they were given the Spielberger State Anxiety Inventory, and asked to rate their performance on a five-point scale. Mean anxiety change scores were -.90,.75, 4.75, and 5.55 for the four alcohol doses, respectively. There was no significant correlation between anxiety change and actual performance on the visual vigilance task, but for males there was a significant correlation between anxiety change and perceived level of impairment. Language: en

W D Gentry

Papers

Effects of alcohol on psychomotor performance of men and women.

Effect of alcohol consumption on state anxiety changes in male and female nonalcoholics.