Week 4 PSY 383 Midterm - Alcohol

Why are depressants so interesting?

Alcohol Consumption

• One of the most commonly used psychoactive substance globally 

What is a depressant? 

Effect & Medical Uses

1. They reduce arousal and stimulation, leading to relaxation, sedation, or sleep 

2. Often prescribed to treat anxiety, insomnia, and pain

Parasympathetic Nervous system

• Controls the “rest and digest” state, allowing the body to relax and recover 

• Slows down heart rate, promotes digestion, and conserves energy

GABA

• The brain’s main inhibitory neurotransmitter

Depressants primarily enhance the activity of GABA

 Barbiturates

• Used for sedation and as anticonvulsants

• Now less common due to overdose risk

Benzodiazepines vs Non-Benzodiazepine Sedatives (Z-Drugs)

• Prescribed for anxiety, insomnia, and seizure disorders & Used for promoting sleep

Opiates?

In their own drug class for pain relief

Dangers of Mixing Depressants

Synergistic Effects & Cross Tolerance

• Combining depressants (e.g., alcohol with benzodiazepines or opioids) can amplify (10x) their effects

• &

• Tolerance to one depressant results in a reduced response to another depressant

  • Even if you haven’t used it before

Cardiovascular Health

• Especially red wine, may raise levels of HDL (good) cholesterol and provide antioxidants

Long term Damage

Liver Damage

Cardiovascular

1. Leads to fat buildup and can cause irreversible scarring (liver failure)

2. Dilates blood vessels and can lead to high blood pressure & Heart attack and stroke risk

Earliest uses

• (Sumerians) Ninkasi the goddess of beer

Middle Ages

Alcohol, especially beer, was often safer than water and widely consumed

Renaissance - 19th Century 

Temperance and Prohibition (1920-1933)

• Industrialization saw an increase in alcohol production and consumption

•  Led to the rise of speakeasies and organized crime

Ethanol vs. other alcohols

Ethanol: Only alcohol safe for consumption

Serving Sizes: 

• Standard drink equivalents 

Rapid Absorption:

• Alcohol is quickly absorbed into the bloodstream compared to other oral drug

Stomach and Small intestine

• Minimal First-Pass Metabolism effect 

Equilibration

• Alcohol is water and lipid-soluble and easily passes through the cell membranes

• Distributes evenly throughout body water (all major organs)

Blood-Brain Barrier 

• Alcohol easily and rapidly crosses (lots of water in brain)

Metabolism 

Primary Site

• Liver metabolizes about 95% of ingested alcohol

Steps in alcohol breakdown:

• Alcohol to acetaldehyde (Toxic) 

• Responsible for hangovers and sickness from alcohol 

Metabolic rate (fixed)

0.5 oz of ethanol per hour (one standard drink)

Elimination

• Alcohol is eliminated at a constant rate, 0.015 BAC per hour

• Rate is unaffected by common get sober myths

Mechanism of Action

• Enhances GABA Activity 

  • Makes the brain less excitable which leads to sedation and calmness

• Inhibits Glutamate

  • Slows Brain activity involved in cognitive and motor functions

 Biphasic Effect 

• At lower BACs (up to 0.05%), people tend to feel more euphoric and energetic

• As BAC increases, the depressant effects dominate, leading to drowsiness and impaired motor functions

Sedatives and Alcohol 

Synergistic Effects

• Greater combined effects, high risk of overdose 

Respiratory Depression

• Slowed or stopped breathing , potentially fatal 

Why is Alcohol Addictive? 

Endorphins & High Dopamine release

Endorphins 

• Alcohol also releases beta-endorphins 

High Dopamine release

• Tags the alcohol as the reason for the calm and euphoria

• Motivates user to drink more

Tolerance

Tolerance 

• With repeated alcohol use, the brain adapts by downregulating GABA receptors and upregulating glutamate receptors

Tolerance builds to some effects but not others

• The "buzz“ is mainly affected

• Coordination and judgment continue to deteriorate regardless of how tolerant you become to feeling drunk

Withdrawal 

Severe symptoms

• In extreme cases, delirium tremens (DTs), which can be fatal

- Alcohol is one of the few substances where withdrawal can be deadly