CNS and Psychiatric Disorders
Delirium, Dementia, Depression
Distinguish delirium (acute onset, fluctuating course, inattention) from dementia (chronic, progressive) and depression (pseudodementia with low mood, anhedonia, preserved orientation). Delirium is a medical emergency: identify and treat precipitants - infection, medications (especially anticholinergics and sedatives), pain, urinary retention, constipation, dehydration, sensory deprivation. Antipsychotics are reserved for dangerous agitation and used at the lowest dose for the shortest time; they do not treat the underlying cause.
Dementia Pharmacotherapy
Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) are used in mild-to-moderate Alzheimer disease; memantine for moderate-to-severe. Benefits are modest and symptomatic. Watch for bradycardia, syncope, GI upset, and weight loss. Avoid anticholinergics, which counteract these drugs and worsen cognition.
Depression and Anxiety
SSRIs are first-line; sertraline and escitalopram are common choices. Citalopram is limited to 20 mg/day in patients over 60 because of QT prolongation. Avoid tricyclics and paroxetine because of anticholinergic burden. Monitor for hyponatremia (SIADH) after starting an SSRI, especially in the first weeks.
Parkinson Disease and Epilepsy
Levodopa/carbidopa is most effective for motor symptoms; avoid metoclopramide and typical antipsychotics, which worsen parkinsonism; quetiapine or low-dose clozapine are preferred for psychosis. In epilepsy, enzyme-inducing antiseizure drugs interact widely, and older adults are sensitive to sedation and ataxia.
Traps
Stems that label acute confusion as "sundowning" or "dementia progression" distract from delirium. Another trap is adding an antipsychotic before addressing pain, retention, or a culprit drug.
Rule of Thumb
Any new behavioral symptom in an older adult is delirium until proven otherwise; review the medication list and screen for pain, constipation, and retention before psychotropics.