Stress and alcohol consumption increase risk of Alzheimer’s disease

A review of the available scientific literature indicates that alcohol consumption and exposure to stress are associated with an increased risk of Alzheimer’s disease and related dementias. However, the specific mechanisms responsible for this association remain unknown. The paper was published in Neurobiology of Stress.

Alzheimer’s disease is a progressive neurological disorder that primarily affects elderly individuals, leading to memory loss, cognitive decline, and personality changes. It is caused by the buildup of abnormal proteins in and around brain cells – amyloid plaques and tau tangles, which disrupt brain function. It is the most common cause of dementia among older adults.

However, Alzheimer’s disease is not the only medical condition that involves progressive degeneration of brain cells leading to cognitive decline. Conditions involving these changes include vascular dementia, Lewy body dementia, and frontotemporal dementia. All these types of dementia share symptoms that are common with Alzheimer’s disease, such as cognitive decline and memory loss, but are caused by different changes in the brain.

Vascular dementia is caused by reduced blood flow to the brain, typically due to strokes or other conditions affecting blood vessels, leading to cognitive impairments. Lewy body dementia is characterized by abnormal deposits of a protein called alpha-synuclein in the brain, causing symptoms such as hallucinations and movement disorders. Frontotemporal dementia affects the frontal and temporal lobes of the brain, leading to changes in behavior, personality, and language skills.

While scientists understand the brain changes that lead to observable psychological symptoms of these conditions (such as abnormal buildup of proteins), the causes and conditions leading to those changes are not sufficiently understood. Study author Laurel R. Seemiller and his colleagues prepared a review of studies that focused on examining the links between exposure to stress and all these types of dementia. They refer to all the mentioned conditions together as Alzheimer’s diseases and related dementias.

The authors note that both stress exposure and alcohol can have immense ramifications at both the individual and societal level. In the U.S. alone, alcohol imposes an annual societal cost of $250 billion, with 1 in 8 deaths attributable to alcohol. Similarly, annual costs attributable to stress are about $300 billion. Studies show that stress and alcohol have a synergistic effect, with alcohol consumption leading to situations that create stress and individuals exposed to stress being more likely to consume alcohol.

Already in adolescence, exposure to alcohol and stress adversely affects both brain structure and function. It can facilitate the development of various psychiatric and neurodegenerative diseases. Chronic alcohol drinking can also lead to inappropriate levels of disinhibition and worsen social anxiety.

In adulthood, individuals who drink alcohol are more likely to be unemployed. On the other hand, higher exposure to stress, such as workplace harassment, makes a person more likely to drink alcohol. In contrast, a study in the Netherlands found that not all stressors are associated with more alcohol use. Individuals with unfavorable employment status and financial difficulties were found to be more likely to abstain from drinking. Divorced women were more likely to be heavy drinkers. In men, divorce was associated with both extremes of alcohol consumption—divorced men were found to be more likely to be both heavy drinkers and to be abstinent (not drink alcohol at all).

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Biochemically, alcohol consumption might impact adult cognition through neuroinflammation. This can, through a complex series of reactions, promote the death of neurons and neurodegeneration. Other studies reported that alcohol may also directly trigger proinflammatory effects in the brain, leading to the degeneration of neurons and reduced creation of new ones.

“Both stress and alcohol have been implicated as possible driving forces in cognitive decline and subsequent development of ADRD [Alzheimer’s disease and related dementias). Brain regions including, but not limited to, the prefrontal cortex, nucleus accumbens, and hippocampus are all impacted throughout a subject’s lifespan by stress and alcohol. Combined, stress and alcohol lead to neuroinflammatory dysfunction and potentially contribute to the etiology of AD [Alzheimer’s diseases],” the authors of this review concluded.

The paper makes a valuable contribution to integrating findings about associations between stress, alcohol use, and cognitive decline. However, it should be noted that this was a review article, not an article presenting original research. Because of this, its conclusions are as good as the studies they were based on.

The review article, “Alcohol and stress exposure across the lifespan are key risk factors for Alzheimer’s Disease and cognitive decline,” was authored by Laurel R. Seemiller, Julio Flores-Cuadra, Keith R. Griffith, Grace C. Smith, and Nicole A. Crowley.