đź“‹ Executive Summary
The 2025 geriatric psychiatry landscape is defined by three converging revolutions: blood-based biomarkers for Alzheimer's diagnosis, refined BPSD management under new safety guidelines, and structural integration through collaborative care models. By 2060, Americans living with Alzheimer's and related dementias is projected to double, necessitating precision medicine approaches.
🧬 Blood-Based Biomarkers (2025 Guidelines)
Alzheimer's Association CPG (July 2025): High-performance blood-based biomarkers (BBMs) democratize access to biological diagnosis.
Two-Tiered Framework
| Tier |
Performance |
Clinical Use |
| Tier 1 (Triaging) |
≥90% sensitivity, ≥75% specificity |
Rules out AD; pivot to other etiologies if negative |
| Tier 2 (Confirmatory) |
≥90% sensitivity AND specificity |
Standalone diagnostic; DMT eligibility pathway |
Primary Target: p-tau217 shows correlation with brain amyloid load comparable to CSF markers.
AGS Caution: Evidence quality graded as "low" or "conditional." Avoid primary care screening—restricted to specialized memory care settings.
🧠BPSD Management (2024 CCSMH Guidelines)
The DICE Approach
- Describe: Behavior as communication—what unmet need?
- Investigate:>Rule out delirium, pain, UTI, sensory deficits
- Create: Psychosocial interventions first
- Evaluate: Response to interventions
Pharmacologic Escalation Ladder
| Symptom |
First-Line |
Second-Line |
Contraindicated |
| Moderate Agitation |
Citalopram (max 20mg) |
Risperidone short-term |
Benzodiazepines (falls risk) |
| LBD/Psychosis |
Pimavanserin |
Clozapine (monitoring) |
All D2 antagonists |
Black Box Warning: Atypical antipsychotics in dementia carry increased mortality risk (1.6-1.7x). Use only for severe symptoms with safety risk.
đź’Š Geriatric Pharmacotherapy
Age-Related Pharmacokinetic Changes
| Parameter |
Change |
Clinical Impact |
| Volume of Distribution |
Increased (more adipose) |
Lipophilic drugs (diazepam) accumulate |
| Hepatic Clearance |
Decreased 30-40% |
Prefer LOT benzodiazepines (lorazepam, oxazepam, temazepam) |
| Renal Function |
GFR declines ~10%/decade |
Dose-adjust lithium, gabapentin, risperidone active metabolite |
Anticholinergic Burden Scale
High Risk (Score 3): Amitriptyline, paroxetine, oxybutynin, diphenhydramine, hydroxyzine. Total score ≥3 associated with cognitive impairment, falls, mortality.
⚕️ Comorbidity Algorithms
Depression in Heart Failure
- Screen with PHQ-9; rule out hypothyroidism, anemia, sleep apnea
- Avoid: TCAs (type 1A antiarrhythmic, anticholinergic)
- Preferred: Sertraline (SADHART-CHF evidence)
- Monitor: QTc with citalopram/escitalopram; hyponatremia with SSRIs + diuretics
Agitation in CKD/ESRD
| Drug |
GFR >60 |
GFR 30-60 |
GFR <30/Dialysis |
| Risperidone | Standard | 0.5mg BID | Start 0.25-0.5mg, max 2mg/day |
| Gabapentin | Standard | 300-600mg BID | Max 300mg daily, post-dialysis |
| Lithium | Standard | Close monitor | Contraindicated (dialyzable) |