Geriatric Psychiatry & Delirium: PMHNP Board Review

Geriatric psychiatry tests your ability to separate "the 3 Ds" — delirium, dementia, and depression — and to prescribe safely in older adults. The single highest-yield point: delirium is an acute, fluctuating disturbance of attention and awareness with an identifiable medical cause, and it is a medical emergency — always rule it out first. A close second: antipsychotics carry a black box warning for increased mortality in elderly patients with dementia-related psychosis.

This review covers the 3 Ds, deliriogenic medications, Beers criteria, and dementia behavioral management.

Why geriatric prescribing is different

Aging changes pharmacokinetics and pharmacodynamics in ways the board expects you to apply. Reduced hepatic and renal clearance prolongs half-lives, decreased lean body mass and increased fat alter distribution (lipophilic drugs like diazepam accumulate), and the aging brain is more sensitive to sedation, anticholinergic effects, and orthostasis. Polypharmacy multiplies interaction risk. These realities explain the universal geriatric mantra — "start low, go slow" — and the emphasis on deprescribing. Older adults are also more vulnerable to falls, which makes sedating and anticholinergic medications doubly hazardous. When a vignette describes a new symptom in an older adult on multiple medications, a medication effect should be high on your differential before you reach for a new diagnosis.

The 3 Ds: delirium vs dementia vs depression

Delirium

• Acute onset (hours to days), fluctuating course.

• Core deficit: inattention plus a change in cognition or perception.

• Altered level of consciousness; often worse at night ("sundowning").

• Caused by an underlying medical condition — infection (UTI, pneumonia), medications, metabolic derangement, hypoxia, withdrawal, post-op states.

• Reversible when the cause is treated. Always rule out and treat delirium first in an acutely confused older adult.

Dementia (major neurocognitive disorder)

• Gradual, progressive decline in one or more cognitive domains.

• Consciousness and attention are preserved until late stages — the key contrast with delirium.

• Generally irreversible (Alzheimer's, vascular, Lewy body, frontotemporal).

Depression ("pseudodementia")

• Cognitive complaints with prominent low mood, anhedonia, and subacute onset.

• Patients often say "I don't know" rather than confabulate; effort is low but cognition is intact when engaged.

• Improves with antidepressant treatment — important because it is reversible and frequently mistaken for dementia.

Board shorthand: acute + inattention + fluctuating = delirium; chronic + progressive + alert = dementia; mood-driven + "don't know" answers = depression.

Deliriogenic medications

Medications are a leading reversible cause of delirium. High-risk classes:

• Anticholinergics (diphenhydramine, oxybutynin, tricyclics) — the most testable culprit.

• Benzodiazepines and sedative-hypnotics.

• Opioids (especially meperidine).

• Corticosteroids.

• Polypharmacy in general.

Management of delirium is to identify and treat the cause, reorient, and use nonpharmacologic measures first. Reserve low-dose antipsychotics for severe agitation that threatens safety. Avoid benzodiazepines except in alcohol/benzo withdrawal delirium, because they worsen confusion.

Working up delirium

The board wants you to think like a detective. A practical workup searches for reversible causes — the classic mnemonics (such as "DELIRIUMS" or "I WATCH DEATH") cue you to check for infection, metabolic and electrolyte derangements, hypoxia, medications, urinary retention or constipation, pain, and withdrawal states. Order a focused evaluation: vital signs and oxygen saturation, urinalysis, basic metabolic panel, CBC, and a careful medication review, escalating to imaging or further studies as the history suggests. Nonpharmacologic prevention and management — frequent reorientation, sleep-wake regulation, early mobilization, sensory aids (glasses, hearing aids), hydration, and family presence — are evidence-based and are the preferred first answer. Physical restraints worsen delirium and agitation and are generally the wrong choice.

Beers Criteria

The AGS Beers Criteria list potentially inappropriate medications in older adults. High-yield examples to avoid or minimize:

• First-generation antihistamines (diphenhydramine) — anticholinergic.

• Benzodiazepines — falls, cognitive impairment.

• Tricyclic antidepressants — anticholinergic, cardiac.

• Muscle relaxants, certain antipsychotics, and sliding-scale insulin.

The overarching principle: "start low, go slow," minimize anticholinergic burden, and avoid sedatives that increase fall and delirium risk.

Dementia: behavioral management

Behavioral and psychological symptoms of dementia (BPSD) — agitation, aggression, wandering, psychosis.

• Nonpharmacologic interventions are first-line: structured routine, redirection, environmental modification, addressing unmet needs and triggers.

• Antipsychotics are last resort and carry the black box warning for increased mortality (largely cardiovascular and infection-related) in elderly patients with dementia-related psychosis. Use only for severe symptoms posing safety risk, at the lowest dose, with documented risk-benefit discussion and reassessment.

• Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) are started in mild-to-moderate Alzheimer's — donepezil and the high-dose (13.3 mg/24 h) rivastigmine patch are also approved for severe disease, while galantamine is limited to mild-to-moderate; memantine (NMDA antagonist) is added in moderate-to-severe disease.

• Lewy body dementia caution: patients are highly sensitive to antipsychotics (severe reactions); avoid first-generation agents.

For agent-specific adverse effects, see our antipsychotic side effects review.

Geriatric depression

Late-life depression is common, underrecognized, and highly treatable. Older adults may underreport sadness and instead present with somatic complaints, anxiety, or cognitive slowing (the pseudodementia picture). SSRIs are first-line because of their favorable safety profile; sertraline and escitalopram are commonly chosen. Avoid agents with high anticholinergic burden — tricyclics and paroxetine are generally poor choices in the elderly. Watch for hyponatremia/SIADH, a notable SSRI risk in older adults, and for increased fall risk. Mirtazapine can be useful when insomnia and poor appetite coexist. Suicide risk is highest in older men, so screening is essential, and ECT remains a safe, effective option for severe, psychotic, or treatment-resistant depression in this population. As with all geriatric prescribing, start low and titrate slowly while allowing adequate time for response.

Dementia types and cognitive assessment

Knowing the major dementia subtypes helps you answer pattern-recognition questions:

• Alzheimer's disease: Most common; insidious memory loss progressing to other domains.

• Vascular dementia: Stepwise decline with cardiovascular risk factors and focal findings.

• Lewy body dementia: Fluctuating cognition, visual hallucinations, parkinsonism, and severe antipsychotic sensitivity.

• Frontotemporal dementia: Early personality/behavior change or language decline, often before memory loss, in younger patients.

Brief cognitive tools — the MMSE, MoCA (more sensitive to mild impairment), and the Mini-Cog — quantify deficits and track change, but they do not by themselves distinguish delirium from dementia; the clinical picture (acuity, attention, fluctuation) does that. Always evaluate for reversible contributors to cognitive decline (B12 deficiency, hypothyroidism, depression, medications) before concluding the impairment is irreversible. This reversible-causes mindset is rewarded throughout the geriatric section.

Capacity, safety, and end-of-life considerations

Geriatric questions also touch on decision-making capacity and safety. Capacity is decision-specific — a patient may lack capacity for complex financial decisions yet retain it for simpler choices — and it is assessed by the patient's ability to understand, appreciate, reason, and communicate a choice, not by diagnosis alone. Screen for elder abuse and neglect when injuries, malnutrition, or caregiver stress are described. As dementia progresses, advance care planning, caregiver support, and attention to caregiver burnout become central, and goals of care shift toward comfort and dignity. The board favors answers that protect autonomy where possible, involve families and surrogate decision-makers appropriately, and prioritize the least restrictive, least harmful intervention.

High-yield board pearls

• Delirium = acute, fluctuating, inattention, medical cause; rule it out first.

• Dementia = gradual, progressive, alert until late.

• Depression/pseudodementia is reversible with antidepressants.

• Anticholinergics are a top deliriogenic and Beers-listed class.

• Antipsychotics carry a mortality black box warning in elderly dementia — nonpharmacologic first.

• Avoid benzodiazepines for delirium (except substance withdrawal).

• "Start low, go slow"; minimize anticholinergic burden.

• Lewy body dementia patients have severe antipsychotic sensitivity.

Common exam traps

• Calling acute confusion "worsening dementia" and missing a treatable delirium (often a UTI or new medication).

• Using a benzodiazepine to calm a delirious older adult — it worsens confusion outside of withdrawal.

• Reaching for an antipsychotic first in dementia agitation instead of nonpharmacologic measures, ignoring the mortality warning.

• Prescribing diphenhydramine for sleep in an older adult (anticholinergic, Beers-listed).

• Treating pseudodementia as irreversible dementia rather than recognizing reversible depression.

• Giving a first-generation antipsychotic in Lewy body dementia.

Geriatric prescribing must follow current Beers Criteria, FDA labeling, and individualized risk-benefit discussion; this review summarizes board concepts, not direction for a specific patient.

Keep building your board readiness

Geriatric questions reward fast pattern recognition of the 3 Ds and disciplined, safety-first prescribing. Sharpen both with targeted practice. Explore the full PMHNP question bank and study tools, find your weak spots with a quick diagnostic assessment, or review the companion pediatric and adolescent psychiatry board review. Ready to start drilling? Create a free account.