Substance Misuse and Addiction

Definition | Aetiology | Pathophysiology | Risk factors | Signs and symptoms | Investigations | Management

Definition

Substance misuse and addiction refer to the harmful or hazardous use of psychoactive substances, including alcohol and illicit drugs, leading to dependence, withdrawal, and social or occupational dysfunction.

Aetiology

  • Biological factors:
    • Genetic predisposition to addiction.
    • Neurochemical imbalances affecting dopamine pathways.
  • Psychological factors:
    • History of trauma or adverse childhood experiences.
    • Co-existing mental health disorders (e.g., depression, anxiety, PTSD).
  • Social factors:
    • Peer pressure and social environment.
    • Socioeconomic deprivation.
    • Availability and accessibility of substances.

Pathophysiology

  • Activation of the brain’s reward system via dopaminergic pathways (mesolimbic system).
  • Chronic substance use leads to neuroadaptations, tolerance, and dependence.
  • Withdrawal symptoms occur due to neurochemical imbalances when substance use is stopped.

Risk factors

  • Family history of substance misuse.
  • Early exposure to drugs or alcohol.
  • Untreated mental health conditions.
  • Unemployment or financial difficulties.
  • History of physical or sexual abuse.
  • Chronic pain conditions requiring opioid use.

Signs and symptoms

  • Behavioural changes: secrecy, neglect of responsibilities, social withdrawal.
  • Physical signs: weight loss, poor hygiene, injection marks (if IV drug use).
  • Psychological symptoms: mood swings, paranoia, hallucinations (with stimulant use).
  • Withdrawal symptoms: sweating, nausea, agitation, tremors, seizures (depending on substance).

Investigations

  • Detailed substance use history: frequency, quantity, duration of use.
  • Blood tests: LFTs (for alcohol misuse), FBC, U&Es, HIV and hepatitis screening.
  • Urine drug screen: to confirm recent substance use.
  • ECG: if stimulant use suspected (risk of arrhythmias).
  • Mental health assessment: to identify co-existing psychiatric conditions.

Management

1. Brief interventions and harm reduction:

  • Motivational interviewing to encourage behaviour change.
  • Needle exchange programmes for IV drug users.
  • Advice on safer drinking limits for alcohol misuse.

2. Pharmacological treatment:

  • Alcohol dependence:
    • Thiamine supplementation (to prevent Wernicke’s encephalopathy).
    • Acamprosate or naltrexone for relapse prevention.
    • Chlordiazepoxide (or diazepam) for alcohol withdrawal.
  • Opioid dependence:
    • Opioid substitution therapy (methadone, buprenorphine).
    • Naloxone for overdose prevention.
  • Nicotine dependence:
    • Nicotine replacement therapy (patches, gums, lozenges).
    • Varenicline or bupropion as pharmacological aids.

3. Psychological support:

  • Cognitive behavioural therapy (CBT) for addiction.
  • 12-step programmes (e.g., Alcoholics Anonymous, Narcotics Anonymous).
  • Peer support groups and relapse prevention strategies.

4. Referral:

  • Drug and alcohol services: for structured support and rehabilitation.
  • Mental health services: for co-existing psychiatric conditions.
  • Social services: if safeguarding concerns exist.
PsychiatrymypanotesSubstance Misuse and Addiction