Alcohol causes short-term and long-term effects on your brain. It takes five minutes for alcohol to reach your brain after you drink it, and ten minutes for it to start affecting you. Heavy or chronic alcohol consumption can also result in long-term brain changes.

Immediate Effects

1. Brain Activity Decreases

Alcohol is a central nervous system depressant, which means it slows down activity in your brain and spinal cord.

In the short-term, alcohol intoxication can reduce activity in multiple parts of the brain, including the:

• Cerebellum: Responsible for coordination, movement, and balance.
• Cortex: The outer layer of the brain responsible for executive reasoning, such as language, memory, behavior, and conscious thought.
• Frontal lobe: The brain’s largest lobe; responsible for personality and decision-making.
• Hippocampus: Associated with memory formation and spatial perception.
• Occipital lobe: Associated with vision.
• Parietal lobe: Helps process sensory information.
• Temporal lobe: Associated with auditory and visual perception, short-term memory, musical rhythm, and speech.

Problems with these brain regions may lead to symptoms associated with each region’s responsibilities.

2. Spatial Cognition is Impaired

There’s a reason that people who are intoxicated tend to stumble, fall, or behave clumsily. Alcohol can affect the way you perceive space because it slows down activity in the hippocampus.

Combined with slower reaction times, this can lead to issues with coordination and potentially lead to injuries.

3. Blackouts and Memory Loss Occur

Heavy alcohol intoxication may lead to blackouts or memory loss. This is because alcohol affects the hippocampi, two structures in the brain that help you form new memories.

4. The Brain’s Reward System is Activated

Drinking alcohol, even small amounts, can lead to a “tipsy” feeling due to your brain’s reward processing system being activated.

Activating these parts of the brain can release neurotransmitters (chemical messengers) like dopamine, which contribute to feelings of pleasure and enjoyment.

5. Pain and Stress Sensations Decrease

Alcohol can heighten feelings of pleasure and dull feelings of pain and stress—but only in the short-term. Alcohol dampens activity in the amygdala, two almond-shaped brain structures responsible for your fight-or-flight response and emotion processing.

Keep in mind that this is only true in the short term. When someone who drinks chronically quits drinking, the amygdala can become hyperactive (called kyperkatifeia) and heighten feelings of stress and pain.

Long Term Effects

1. Alcohol Use Disorder May Develop

Drinking alcohol may lead to dependence due to changes in the brain’s reward and stress systems. Alcohol use disorder (AUD) is when someone feels compelled to repeatedly drink alcohol, despite the harmful effects that alcohol may have on them or their lives.

This happens, in part, because alcohol causes changes in the brain (called plasticity). Heavy drinking leads to changes in brain regions that control:

• Attention
• Decision making
• Impulse control
• Memory
• Motivation
• Sleep

Additionally, when someone drinks alcohol repeatedly, the stress systems in their brain are increasingly activated, and the reward system is reduced. This effect is in contrast to alcohol’s short-term effects on the brain.

Due to these brain changes, alcohol use switches from being a form of positive reinforcement (that makes them feel good) to a negative reinforcement (because it lessens symptoms of withdrawal or stress). Thus begins the cycle of alcohol dependence.

2. White Matter Decreases

White matter is located in the deeper (subcortical) areas of the brain. It contains nerve axons and is where messages are transmitted between nerve cells. Heavy alcohol drinking can lead to a loss of white matter volume and changes in its microstructure.

Alcohol-related changes can happen anywhere in the white matter, but particularly in the corpus callosum, which connects the right and left hemispheres of the brain and helps them communicate with each other.

3. Gray Matter is Damaged

Gray matter makes up the outer layer of the brain. Heavy, long-term drinking can lead to gray matter volume loss in the brain. This gray matter loss mimics that which occurs as people age, meaning that the brains of people with AUD may appear much older than what is considered “normal” for their chronological age.

4. More Brain Areas Shrink

Between the white matter and gray matter loss, heavy alcohol drinking can lead to generalized volume loss across the whole brain.

Studies that use imaging to look at brain structure have found that people with AUD have damage to brain regions that are associated with:

• Cognition
• Emotional processing
• Memory

5. Neurotoxity Occurs

Alcohol can act as a neurotoxin, meaning it can damage and kill nerve cells in your brain. It does this through three pathways:

• Neuroinflammation: Alcohol can significantly increase inflammation in the body. Inflammatory molecules can cross the blood-brain barrier and cause damage to the brain.
• Thiamine deficiency: Heavy alcohol drinking can make it harder for your body to absorb thiamine (Vitamin B1), an essential vitamin. Without thiamine, nerve cells can be destroyed, and conditions like Wernicke encephalitis or Wernicke-Korsakoff syndrome can develop.
• Toxicity: When the body breaks down alcohol, it produces acetaldehyde, which is toxic and can cause damage to nerves.

6. Long Term Memory Conditions May Develop

Drinking too much alcohol over multiple years can lead to memory conditions similar to dementia. Some of these conditions are reversible, and some are permanent.

These conditions are grouped under the umbrella of alcohol-related brain damage (ARBD). These include:

• Alcohol-related dementia: Damage to the brain due to alcohol consumption can cause dementia, which comes with memory loss, poor short-term memory, behavior and personality changes, and more. Even light to moderate alcohol drinking in middle or old age can contribute to alcohol-related dementia.
• Alcohol-related stroke: A stroke occurs when blood flow to the brain is altered, either by a blockage or a bleed. Alcohol can contribute to strokes by raising blood pressure.
• Mild cognitive impairment (MCI): A minor decline in memory and thinking, due to brain changes.
• Wernicke-Korsakoff syndrome: A neurological condition similar to dementia, caused by a thiamine deficiency, and often due to alcohol.

Indirect Effects

Drinking too much alcohol can increase the risk of physical trauma, including head injuries that may result in brain damage. This could range from stumbling and hitting your head to blacking out on pavement to being hit during a fight or assault.

Heavy drinking can also lead to seizures and stroke. It also affects other organs throughout the body, like the:

• Digestive system
• Heart
• Kidneys
• Liver
• Lungs
• Pancreas

All of this can indirectly affect the brain.