Alcohol

Overview – Alcohol

Alcohol is a widely consumed psychoactive substance that modulates inhibitory and excitatory neurotransmission, stimulates the dopamine reward pathway, and contributes to significant global morbidity and mortality. In clinical practice, alcohol misuse is frequently encountered and implicated in a wide range of physical, psychiatric, and social issues. This article reviews alcohol’s neurobiology, health effects, dependence criteria, screening tools, withdrawal syndromes, and evidence-based management strategies.

Definition

• Alcohol use refers to the consumption of ethanol-containing beverages.
• Alcohol dependence is characterised by tolerance, withdrawal, and loss of control over use.

Why Do People Drink?

• Pleasure (taste, relaxation)
• Anxiolytic effects (reduces anxiety)
• Self-medication for trauma, stress, or domestic problems
• Psychiatric comorbidities (e.g. depression, eating disorders, history of abuse)
• Genetic predisposition or family history of alcoholism

Mechanism of Action

• ↑ GABA activity → CNS inhibition
• ↓ Glutamate activity → ↓ excitatory tone
• Stimulates mesolimbic dopamine reward pathway

Epidemiology

• Alcohol contributes to:
  • 50% of assaults
  • 30% of road traffic accidents
  • 12% of suicides
  • 10% of industrial injuries
• Male consumption patterns:
  • 48% drink weekly
  • 12% drink daily
  • 10% drink at hazardous levels
• Female consumption patterns:
  • 35% drink weekly
  • 6% drink daily
  • 10% drink at hazardous levels

Alcohol Measurement

• 1 standard drink = 10g pure alcohol
  • = 30ml spirits
  • = 285ml beer
  • = 100ml wine
  • = 60ml port
• Alcohol content can be calculated using:
  • Volume × %Alcohol × Specific Gravity (0.789) ÷ 10 = standard drinks

Clinical Features

Adverse Effects

Psychosocial:

• Relationship breakdown
• Domestic violence
• Crime and driving offences
• Depression, anxiety, irritability, memory loss
• Suicide attempts

Physical:

• Brain damage (irreversible)
• Wernicke-Korsakoff syndrome
• Epilepsy
• Liver disease (fatty liver, hepatitis, cirrhosis)
• Cardiovascular: hypertension, cardiomyopathy
• Gastrointestinal: ulcers, gastritis, pancreatitis
• Endocrine/metabolic: obesity, osteoporosis, gynecomastia, gout
• Haematological: macrocytic anaemia, thrombocytopenia, leukopenia
• Cancer (liver, gastrointestinal tract, head and neck)
• Neurological: tremors, peripheral neuropathy (e.g. Dupuytren’s contracture)

Alcohol Dependence

• Defined by tolerance, compulsive use, and withdrawal symptoms
• Early-onset drinking (<15 years) increases risk of dependence 4-fold

Screening Tools

• CAGE Questionnaire (score ≥2 suggests dependence):
  • Cut down
  • Annoyed
  • Guilty
  • Eye-opener
• AUDIT (Alcohol Use Disorders Identification Test)
  • 10 questions, risk-tiered score
  • Gender-adjusted thresholds

Biological Markers

• ↑ Mean corpuscular volume (MCV)
• ↑ Gamma-glutamyl transferase (GGT)
• Fatty liver
• Hepatitis
• Cirrhosis

Alcohol Withdrawal

• One of the only two life-threatening withdrawal syndromes (other: benzodiazepines)
• Mortality: 2–10% (commonly from arrhythmia or pneumonia)
• Severity assessed via CIWA score

Symptoms

Simple withdrawal:

• Anxiety, agitation, insomnia, depression
• Tremor
• Nausea, vomiting
• Sympathetic overdrive: tachycardia, sweating

Complex withdrawal – Delirium Tremens:

• Onset: 1–14 days post-cessation
• Lasts: 1–6 days
• Predisposing factors:
  • Age >30
  • Daily heavy use
  • Prior DTs or withdrawal seizures
  • ↑GGT or MCV
  • Concurrent alcohol-related disease

DT Pathophysiology:

• ↑ Cardiac workload
• Hyperventilation → respiratory alkalosis → ↓ cerebral perfusion
• Electrolyte disturbances:
  • ↓ potassium (renal losses)
  • ↓ magnesium (→ seizures)
  • ↓ phosphate (→ heart failure)

Clinical features:

• Tonic-clonic seizures
• Hypervigilance, hallucinations, agitation
• Hyperthermia, hypertension
• Arrhythmias, cardiac arrest
• Risk of stroke

Management

Withdrawal Treatment

• First-line: diazepam (benzodiazepine taper)
• Supportive care:
  • Antiemetics, antidiarrhoeals
  • Electrolyte repletion
  • Vitamin B1 (thiamine) supplementation

Preventative Measures

• Early recognition and brief interventions
• Motivational interviewing
• Alcohol history, social/lifestyle assessment
• Physical exam and blood tests (MCV, LFTs)

Pharmacotherapy for Dependence

• Considered in dependent individuals:
  • Naltrexone
  • Acamprosate
  • Disulfiram (less commonly used)

Behavioural Support

• Counselling and CBT
• Goal setting and coping strategies
• Referral to specialist addiction services

Wernicke-Korsakoff Syndrome

• Preventable, but often irreversible neurological complication
• Caused by thiamine deficiency due to chronic alcohol use
• Alcohol impairs thiamine absorption
• Wernicke’s encephalopathy triad:
  • Ophthalmoplegia
  • Ataxia
  • Confusion
• Korsakoff’s syndrome:
  • Anterograde and retrograde amnesia
  • Confabulation
• Requires urgent parenteral thiamine
• Poorly treated cases → 75% permanent brain damage
• 20% require lifelong institutional care

Summary – Alcohol

Alcohol is a widely consumed central nervous system depressant that impacts physical, psychological, and social health. From neurochemical changes and dependence to withdrawal syndromes and Wernicke-Korsakoff encephalopathy, understanding the full spectrum of alcohol-related complications is essential for safe and effective clinical practice. For a broader context, see our Psychiatry & Mental Health Overview page.