- Alcohol is a legal, depressant drug.
- It is a liquid produced by fermentation. Further processing produces alcoholic drinks such as beer, wine, cider and spirits.
- Pure alcohol has no colour. It has a very strong taste that feels like a burning sensation.
At low doses a person may experience the following:
- mental relaxation
- reduced stress
- reduced concentration
- inhibits memory (useful for survivors of trauma)
- relaxes the muscles
- dulls pain
- slower reflexes
- social lubricant - reduced shyness or anxiety
At moderate doses a person may experience the following:
- fewer inhibitions
- more confidence
- reduced coordination
- slurred speech
- intense mood
At high doses a person may experience the following:
- blurred vision
- poor muscle control
- aggression and violence
- alcohol poisoning in large doses depending on tolerance levels
- possibly coma or death
- loss of coordination
- irregular or slow breathing (less than eight breaths a minute)
- blue-tinged or pale skin
- low body temperature (hypothermia)
- stupor (being conscious but unresponsive)
- unconsciousness (passing out)
The effects of alcohol on the brain occur within 5 minutes or alcohol being consumed.
When someone drinks heavily, they may experience a range of symptoms the following day. These symptoms are called a hangover and may include:
- sensitivity to light and sound
- reduced appetite
- increased heart rate and blood pressure
- dehydration (dry mouth, extreme thirst, dry eyes)
- trouble concentrating
- difficulty sleeping.
Sobering up takes time. The liver gets rid of about one standard drink an hour. Cold showers, exercise, black coffee, mints, fresh air or vomiting will not speed up the process. Someone who drinks a lot at night, may still be affected by alcohol the following day.
Alcohol is rapidly absorbed from the small bowel via portal circulation (around 80%), and stomach (around 20%). Alcohol is water soluble, and little or no alcohol enters fatty tissue. It reaches the brain within five minutes of ingestion, with blood concentrations peaking between 30 to 90 (typically 45) minutes.
- Increases the inhibitory effects of GABA and decreases the excitatory effects of glutamate.
- Reinforcing effects probably related to increased activity in mesolimbic dopamine pathway.
People who drink heavily on a regular basis may become dependent on alcohol. They may also develop a tolerance to it, which means that they will need to drink larger amounts of alcohol to get the same effect. Tolerance develops due to increased metabolism in the liver, and changes to receptors in the brain.
- People who are psychologically dependent on alcohol may feel an urge to use it when they are in specific situations.
- Physical dependence occurs when a person's body adapts to alcohol and gets used to functioning with it present.
If a dependent person stops drinking alcohol, they may experience withdrawal symptoms because their body has to get used to functioning without the drug.
- Withdrawal symptoms usually start about 4-12 hours after the last drink and can last 4-5 days. These symptoms include:
- Withdrawal from alcohol carries the risk of seizures or fits. Medical assistance may be required to help the person get through withdrawal safely.
Short-term risks include:
- driving while intoxicated
- unwanted or unsafe sex
- interpersonal conflict
- aggression and violence
Long-term, heavy use of alcohol can lead to a range of neurobiological adaptations including decreased levels of gamma-aminobutyric acid (GABA), a neurotransmitter that inhibits electrical activity in the brain, and to reduced sensitivity of GABA receptors. These effects, coupled with over stimulation of glutamate (an excitatory neurotransmitter) and an increase in glutamate receptors are thought to contribute to the Central Nervous System hyperactivity which characterises many of the symptoms of alcohol withdrawal following reduction or cessation of use.
- Altered brain function and structure, particularly in prefrontal cortex including cognitive impairment and decreased brain volume
- Cardiovascular disease:
- haemorrhagic stroke
- raise high-density lipoprotein cholesterol
- Mental health problems:
- anxiety disorders
- oral cavity
- female breast
- Nutrition related conditions:
- Wernicke-Korsakoff syndrome
- folate deficiency
- Vitamin A and B3 depletion
- Liver disease
- fatty liver
- Tolerance and dependence
- Foetal alcohol syndrome – characterised by:
- low birthweight
- smaller than normal head circumference
- small eyes
- flattened face and heart defects.
- Later in life, affected children might experience low IQ, developmental delays, behavioural problems, learning difficulties and memory problems.