Geriatric Psychiatry
Core distinctions
The central skill is separating delirium, dementia, and depression (the "3 Ds"). Delirium is acute, fluctuating, with impaired attention and altered consciousness; dementia is chronic, progressive cognitive decline with preserved consciousness until late; depression causes pseudodementia with prominent mood change and "don't know" answers.
Know the dementias: Alzheimer's (insidious memory loss, hippocampal atrophy), vascular (stepwise, focal signs), Lewy body (fluctuating cognition, visual hallucinations, parkinsonism, neuroleptic sensitivity), frontotemporal (personality/behaviour or language variants, younger onset).
Assessment and management
Use cognitive screening (MMSE, MoCA) with caution - education and culture affect scores. Always screen for reversible causes (B12, thyroid, depression, drugs, infection, subdural, normal pressure hydrocephalus). Manage behavioural and psychological symptoms of dementia (BPSD) with non-pharmacological measures first; antipsychotics carry increased mortality and stroke risk in dementia and should be time-limited.
Traps
- Missing delirium superimposed on dementia - a common and fatal combination.
- Prescribing antipsychotics long-term for BPSD without review.
- Attributing late-onset psychosis to schizophrenia when organic causes are more likely.
- Forgetting elder abuse and capacity assessment.
Rule of thumb
Any acute change in cognition or behaviour in an older person is delirium until proven otherwise - find the cause (infection, drugs, pain, constipation, retention, environment).