#164 - Amanda Smith, M.D.: Diagnosing, preventing, and treating Alzheimer's disease, and what we can all learn from patients with dementia

Episode Summary

Executive Summary: Peter Atiyah interviews Dr. Amanda Smith about Alzheimer’s disease, dementia diagnosis, and the evolving treatment pipeline. They cover how geriatric psychiatry fits into memory care, why clinical history and informant input remain central to diagnosis, how amyloid/tau and vascular disease interact, and why prevention and earlier intervention are increasingly the field’s focus. The conversation also explores caregiver burden, behavioral symptoms, and healthy aging.

Main Topics: Path into geriatric psychiatry and Alzheimer’s care (Priority: 5/5): Smith explains how growing up around active grandparents and witnessing ageism in medicine led her to geriatric psychiatry and dementia care. Clinical diagnosis of dementia and Alzheimer’s disease (Priority: 5/5): The discussion emphasizes that diagnosis still depends heavily on patient history, informant history, cognitive testing, imaging, and labs, with biomarkers as helpful but not always necessary or accessible. Differentiating Alzheimer’s, Lewy body dementia, vascular dementia, and FTD (Priority: 5/5): Smith outlines classic symptom patterns for each syndrome, including memory-first decline in Alzheimer’s, hallucinations and parkinsonism in Lewy body disease, and behavior/language changes in frontotemporal dementia. Amyloid, tau, and mixed pathology (Priority: 5/5): They discuss amyloid as a defining pathology of Alzheimer’s, tau as more closely tied to symptom spread, and the frequent reality of mixed disease with vascular contributions. Therapeutic pipeline and aducanumab controversy (Priority: 5/5): The episode reviews the large Alzheimer’s drug pipeline, the shift toward disease-modifying therapies, and the high-stakes FDA decision around aducanumab and ARIA risk. Caregiver burden, behavioral symptoms, and psychiatric treatment (Priority: 4/5): Smith stresses that most dementia patients develop mood or behavioral symptoms and that caregiver support, education, and symptom-targeted treatment are essential. Healthy aging, identity, and quality of life (Priority: 4/5): The conversation closes on aging well through relationships, acceptance, staying engaged in the present, and not over-identifying with declining physical or cognitive abilities.

Key Arguments: A dementia diagnosis is primarily clinical: the best assessment comes from interviewing both the patient and an informant separately, then integrating cognitive testing, imaging, and labs. Alzheimer’s disease is defined pathologically by amyloid plaques and tau tangles, but in living patients diagnosis is probabilistic and often supported by amyloid PET or CSF biomarkers. Amyloid accumulation can begin 10-20 years before symptoms, which is why prevention and preclinical intervention are increasingly important. Tau appears more closely linked to symptom expression and disease staging than amyloid alone. Most older patients have mixed pathology rather than a single pure dementia cause; vascular disease is especially common alongside Alzheimer’s. Behavioral and psychiatric symptoms are common in dementia and are often treatable with SSRIs and other carefully chosen medications, while benzodiazepines are generally avoided due to confusion and fall risk. Caregivers need education and reframing because many difficult behaviors are disease-driven rather than intentional. Healthy aging depends less on preserving every physical or cognitive function and more on maintaining relationships, purpose, and the ability to adapt to loss. Exercise remains beneficial even after cognitive impairment develops and may improve cognitive test performance. The field is shifting from late-stage symptomatic treatment toward earlier disease modification and prevention, but clinical endpoints remain difficult to measure reliably.

Data Points: Alzheimer’s drug pipeline: Over 100 drugs - Smith and Atiyah discuss the size of the regulatory pipeline for Alzheimer’s therapies. Phase 1 drugs: 27 - Approximate number of Alzheimer’s drugs in phase 1 trials. Phase 2 drugs: 65 - Approximate number of Alzheimer’s drugs in phase 2 trials. Phase 3 drugs: 29 - Approximate number of Alzheimer’s drugs in phase 3 trials. Pipeline categories: 12 cognitive enhancement, 12 neuropsychiatric/behavioral, 97 disease-modifying - Breakdown of Alzheimer’s drugs by therapeutic intent. FDA-approved symptomatic drugs: 6 total, including one combination product - Current approved Alzheimer’s medications discussed as symptomatic rather than disease-modifying. Aricept approval year: 1997 - Smith notes she graduated the same year donepezil (Aricept) was first approved. Amyloid PET vs autopsy correlation: ~97% - Correlation cited between amyloid PET findings and post-mortem brain pathology in a validation study. Amyloid buildup before symptoms: 10-20 years - Amyloid can accumulate long before cognitive symptoms appear. Typical duration of failed late-stage anti-amyloid trials: ~18 months - Earlier trials in mild-to-moderate disease were often too short and too late in the disease course. Delay in nursing home placement with donepezil: 24 months - Smith cites an old study suggesting donepezil delayed nursing home placement on average. Behavioral symptoms prevalence: ~90% - Smith says most people with dementia will have some behavioral issue at some point. Lewy body dementia duration: ~8-10 years - Estimated course from diagnosis to severe disability or death. Clinic case mix: 50-60% Alzheimer’s, ~20% vascular, ~20% Lewy body, remainder FTD/other - Smith’s approximate distribution of diagnoses in her practice. Drug development cost: ~$1-1.4 billion per approved drug - Atiyah and Smith discuss the cost and long timeline of drug development. Drug attrition: 4,000-5,000 compounds fail for each one approved - General pharmaceutical development attrition rate cited in the discussion.

Pivotal Quotes: "The real crux of diagnosis is a good clinical interview with a patient and with an observer." — Dr. Amanda Smith: On how dementia is diagnosed in practice, emphasizing patient and informant history. "It’s like grieving for someone while they’re still alive." — Dr. Amanda Smith: On the emotional experience of Alzheimer’s disease for families and caregivers. "The key for me really is how that shapes our attitude or how much we let it affect our attitude." — Dr. Amanda Smith: On healthy aging and adapting to physical and cognitive decline.

Implications: The episode reinforces that Alzheimer’s care is moving earlier, more biomarker-driven, and more prevention-focused, but diagnosis and outcomes still rely on nuanced clinical judgment. For listeners, the biggest takeaways are to prioritize vascular risk reduction, exercise, caregiver support, and planning for aging before decline accelerates.