This was a Medscape Psychiatry commentary featured in November.
The guidelines for safe or “low-risk” alcohol consumption have been greatly discussed and debated in recent years, and tend to vary widely around the world. Concerns over harmful and excessive alcohol consumption are warranted, with alcohol’s considerable contribution to the total global burden of disease and injury as well as its known association with major noncommunicable diseases and high-risk behavior. Recommended guidelines for alcohol consumption in the United States, United Kingdom, and Australia are one to two standard drinks a day for women and two standard drinks a day for men, with a suggested one or two alcohol-free days per week.[3-5] Heavy drinking is characterized by exceeding these recommendations both in volume and frequency. Many researchers agree that the volume of alcohol consumed tends to determine the consequences; higher levels of consumption have been linked to adverse physical and mental health outcomes, whereas moderate consumption may be protective and even beneficial for some health conditions.
The high comorbidity between heavy drinkers and mental illness is well documented.[6-8] Given the social, environmental, and lifestyle factors that contribute to drinking behavior, the relationship between alcohol and mental health is complex. Although alcohol is classified as a depressant, its mood-modulating properties are sought by social and casual drinkers, often to the benefit of their health. Conversely, chronic and excessive consumption of alcohol—frequently as self-medication or as a coping mechanism—is markedly toxic and increases the risk for a host of physical and mental disorders. Here we aim to discuss some of the complexities of the relationship between alcohol consumption and mental health, noting the importance of dosage and highlighting the impact on important biological systems for physical and mental health.
Alcohol and Mental Health
It is well documented that substance use disorders and mental illness—particularly mood and behavioral disorders—often co-occur, and that having one increases your chances of developing the other.[10,11] This overlap can be partly understood by the shared social and biological risk factors of alcohol abuse and mental disorders. Both disorders tend to be more prevalent among those who endure chronic stress, either systematically through socioeconomic disadvantage and/or lower levels of education or through familial/social factors, illness, or trauma.
There is evidence to suggest that excessive drinking, among other risky lifestyle behaviors such as smoking, poor diet, or physical inactivity, may be a significant risk factor in the development of some mental disorders. Further, individuals with poorer mental health are more likely to use substances such as alcohol as a coping mechanism and are at higher risk for harmful drinking. While excessive drinking may be a short-term stress-management strategy, the physiologic and behavioral consequences of heavy drinking may create a cycle of risk, contributing to a worsening of mental health or to complications in the treatment or management of a mental disorder.
Alcohol and the Brain: The Bad and the Good
Using alcohol within the recommended boundaries, compared with drinking to excess, affects the body and brain in different ways. For instance, moderate drinking may have anti-inflammatory health benefits and has been linked to enhanced memory, reduced disease risk, and longevity, though research suggests that there is no such safe level of consumption in terms of cancer. Chronic heavy drinking, however, has been shown to be disruptive to the stress response system, inflammatory response, and gut microbiome and to promote oxidative stress—all known risk factors for a variety of physical and mental health conditions.[16,17] Researchers now understand the inflammatory nature of some mental disorders and the connection between this inflammation and the health of the gut. Heavy drinking is disruptive to the healthy balance and structure of the gut microbiome, and binge drinking has been shown to cause endotoxemia—also known as “leaky gut.” New research points to gut health as an important determinant of overall health.
Damage from chronic alcohol use is observed also in the brain, with studies showing less white matter and smaller hippocampal volume in the brains of adults with a history of alcohol abuse, indicating neural loss or dysfunction. Additionally, heavy alcohol consumption promotes a heightened stress response via cortisol pathway deregulation and overactivation of the hypothalamic-pituitary-adrenal axis and may also disrupt the dopaminergic and serotonergic systems. These structural and signaling effects can be problematic on their own but also increase risk for dementia, Alzheimer disease, decreased cognitive function, and mood disorders.[10,24] It is difficult to discern whether alcohol consumption is cause or consequence of a mental condition, and more research is required to understand the direction of this relationship.
For the full article and references go here.