The dopamine system and alcohol dependence
Past guidance around alcohol use generally suggests a daily drink poses little risk of negative health effects — and might even offer a few health benefits. Many people assume the occasional beer or glass of wine at mealtimes or special occasions doesn’t pose much cause for concern. But drinking any amount of alcohol can potentially lead to unwanted health consequences. By Geralyn Dexter, PhD, LMHCDexter has a doctorate in psychology and is a licensed mental health counselor with a focus on suicidal ideation, self-harm, and mood disorders.
Depending on the neurotransmitter involved, this binding leads to the electrical excitation or inhibition of subsequent neurons in the circuit. (For more information on nerve signal transmission, neurotransmitters, and their receptors, see the article by Lovinger, pp. amp on drug screen 196–214.) Alcohol interacts with several neurotransmitter systems in the brain’s reward and stress circuits. Following chronic exposure, these interactions result in changes in neuronal function that underlie the development of sensitization, tolerance, withdrawal, and dependence. Research using pharmacological, cellular, molecular, imaging, genetic, and proteomic techniques already has elucidated details of some of these alcohol effects, and some of these findings will be discussed in other articles in this and the companion issue of Alcohol Research & Health. As a foundation for this discussion, the following sections briefly introduce some of the neural circuits relevant to alcohol dependence, categorized by neurotransmitter systems; however, this discussion is by no means exhaustive.
Alcohol use disorder: pathophysiology, effects, and pharmacologic options for treatment
AA is self-financing and the seventh tradition is that AA groups should decline outside contributions. In 2010, AA membership worldwide was reported as nearly 2 million (Alcoholics Anonymous, 2010). While AA might not suit all people who misuse alcohol, its advantages include its wide availability and open access. The 2004 ANARP found that only one out of 18 people who were alcohol dependent in the general population accessed treatment per annum.
What is Post Acute Withdrawal Syndrome (PAWS)?
- However, because there were few total deaths in ethnic minority groups this may lead to large errors in estimating prevalence in this population.
- These varying results may be due to the use of different animal models or different research protocols.
- Ethanol (or ethyl alcohol) in alcoholic beverages is produced by the fermentation of sugar by yeast.
- In male rats, both acute and chronic alcohol exposure during adolescence results in a reversible suppression of serum testosterone (Little et al. 1992; Cicero et al. 1990; Tentler et al. 1997; Emanuele et al. 1998, 1999a, b; Steiner et al. 1997).
- Several studies have shown that changes in the DA system in the CNS can influence drinking behaviors both in animals and in humans.
These costs include expenditures on alcohol-related problems and opportunities that are lost because of alcohol (NIAAA, 1991). Homeless people who misuse alcohol have particular difficulties in engaging mainstream alcohol services, often due to difficulties in attending planned appointments. Al-anon uses the same 12 steps as AA with some modifications and is focused on meeting the needs of friends and family members of alcoholics. Again, meetings are widely available and provide helpful support beyond what can be provided by specialist treatment services.
Harmful alcohol use and dependence are relatively uncommon before the age of 15 years, but increase steeply to reach a peak in the early 20s, this being the period when alcohol use-disorders are most likely to begin. One US general population study found the prevalence of alcohol dependence to be 2% in 12- to 17-year-olds, rising to 12% in 18- to 20–year-olds (Grant et al., 2004a). The same US study found the prevalence of dependence was 4% in 30- to 34-year-olds and 1.5% in 50- to 54-year-olds. A similar UK study found the prevalence of alcohol dependence to be 6% in 16- to 19-year-olds, 8.2% in 20- to 24–year-olds, 3.6% in 30- to 34-year-olds and 2.3% in 50- to 54–year-olds (Drummond et al., 2005). Therefore, it is clear that there is substantial remission from alcohol-use disorders over time.
Alcohol’s role in co-occurring disorders
Samples were collected from the nucleus accumbens of alcohol-dependent mice that had undergone three cycles of chronic intermittent alcohol vapor exposure (red symbols) and nondependent controls (black symbols). Samples were taken before, during, and after the 2-hour drinking session, when the mice had the opportunity to voluntarily drink alcohol (15 percent vol/vol) or water. Alcohol intake during the drinking session was 3.04 ± 0.15 g/kg for dependent mice and 2.32 ± 0.28 g/kg for nondependent mice. Horizontal lines and shaded area represent brain alcohol levels (means ± SEM) measured in the dependent mice during chronic intermittent alcohol exposure (28.4 ± 3.5 mM). While drinking and alcohol-use disorders are relatively rare under the age of 10 years, the prevalence increases steeply from the teens to peak in the early 20s. The UK has the highest rate of underage drinking in Western Europe (Hibell et al., 2009).
The prevalence of alcohol-use disorders declines with increasing age, but the rate of detection by health professionals may be underestimated in older people because of a lack of clinical suspicion or misdiagnosis (O’Connell et al., 2003). Nevertheless, the proportion of older people drinking above the government’s recommended levels has recently been increasing in the UK. The proportion of men aged 65 to 74 years who drank more than four units per day in the past week increased from 18 to 30% between 1998 and 2008 (Fuller et al., 2009). In women of the same age, the increase in drinking more than three units per day was from 6 to 14%. Also, as noted earlier, alcohol-related admissions to hospital increase steeply with age although the prevalence of heavy drinking is lower in this group.
Alcohol abuse was defined as a condition in which a person continues to drink despite recurrent social, interpersonal, health, or legal problems as a result of their alcohol use. A person who abuses alcohol may also be dependent on alcohol, but they may also be able to stop drinking without experiencing withdrawal symptoms. In addition to the problems presented by comorbid disorders, the concept of dependence and criteria for diagnosis (DSM–IV or ICD–10) has limitations when applied to adolescents because of the low prevalence of withdrawal symptoms and the low specificity of tolerance in this age group (Chung et al., 2001). The adolescent therefore may continue drinking despite problems, which manifest as difficulties with school attendance, co-morbid behavioural difficulties, peer affiliation and arguments at home. All of this points to the importance of addressing the needs of family members of people who misuse alcohol.