Psychiatry
Psychiatry tests structured assessment, risk formulation, and safe prescribing rather than diagnostic labels alone.
Core rules
- Mental state examination: appearance, behaviour, speech, mood and affect, thought form and content, perception, cognition, insight, risk.
- Depression: core symptoms for ≥2 weeks with functional impairment; screen for bipolar disorder before starting an antidepressant.
- Suicide risk: ask directly; document intent, plan, means, previous attempts, and protective factors; means restriction saves lives.
- Delirium versus dementia: acute onset, fluctuating attention, and altered consciousness indicate delirium; look for infection, drugs, and metabolic causes.
- Serotonin syndrome: clonus, hyperreflexia, agitation, fever after serotonergic drugs - stop the agents, supportive care, cyproheptadine in severe cases.
Worked example
A 62-year-old on warfarin, started on fluconazole for candidiasis, presents with confusion. Consider the drug interaction first: azoles inhibit CYP2C9 and raise the INR. Check INR, hold warfarin, and treat the delirium's cause. If a serotonergic agent were the trigger, look for inducible clonus in the lower limbs rather than tremor alone.
Traps
- Starting an SSRI without screening for bipolar disorder - risk of mania.
- Labelling delirium as dementia and missing sepsis.
- Avoiding questions about suicide because of discomfort.
- Missing alcohol withdrawal: tremor, tachycardia, seizures 6–48 hours after the last drink.