Substance Pharmacology, Dependence and Withdrawal
Alcohol, opioids, sedatives, stimulants, cannabis, hallucinogens, solvents and novel substances, including dependence, intoxication, withdrawal and detoxification.
How to prepare for MRCPsych Paper B
Integrate clinical formulation, safety and current UK practice with disciplined appraisal of design, bias, estimates and applicability.
Core concepts
Concept 1
Substance assessment identifies agent, dose, route, pattern, timing, tolerance, dependence, intoxication, withdrawal, physical complications, mental state and interactions.
Exam cue: Build a timeline linking last use and co-use to observed autonomic, neurological, behavioural and mental-state findings.
Concept 2
Withdrawal management is substance-specific and risk-stratified; acute stabilisation, monitoring and a longer-term recovery plan are distinct but connected tasks.
Exam cue: Decide whether the person needs emergency treatment, monitored withdrawal, maintenance or relapse-prevention care.
Risk pitfalls and guardrails
Assuming a toxicology result proves current impairment, dependence or the cause of the presentation.
Guardrail: Do not choose an option because it is merely familiar or associated; show why it best answers this lead-in.
Starting detoxification without assessing severe withdrawal risk, other sedatives, physical illness and aftercare.
Guardrail: Do not convert a group association or score into certain individual prediction or a stand-alone disposition decision.
Memory anchors
What defines dependence clinically?
A cluster involving impaired control, priority of use and persistence despite harm, often with tolerance or withdrawal.
Why is alcohol withdrawal potentially dangerous?
Seizures, delirium and autonomic instability can occur and require risk-based monitoring and treatment.
What is tolerance?
A reduced effect with repeated exposure or a need for a larger dose to obtain a previous effect.
What should an overdose assessment include?
Airway, breathing and circulation, agent and timing, co-ingestants, observations, examination, investigations and appropriate antidote or supportive care.
Why plan after withdrawal?
Detoxification alone does not address craving, triggers, comorbidity, social context or relapse risk.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
A person needs increasing amounts of alcohol to achieve the previous effect. What phenomenon is this?
A person continues cocaine use despite myocardial injury and repeated attempts to stop. Which feature of dependence is illustrated?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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