A 68-year-old woman is brought to the psychiatry outpatient clinic by her daughter with a 2-year history of progressive memory loss, difficulty finding words, and getting lost in familiar places. Over the past 6 months, the family reports increasing irritability, suspiciousness of family members, and occasional accusations that her husband is stealing from her. She has become withdrawn and no longer engages in social activities she previously enjoyed. On cognitive testing, she scores 18/30 on the Mini-Cog. Brain MRI shows global cerebral atrophy with prominent hippocampal shrinkage. Which of the following psychiatric symptoms in this patient is most consistent with the expected neuropsychiatric profile of Alzheimer disease?

Explanation

## Neuropsychiatric Manifestations of Alzheimer Disease **Key Point:** Delusions and behavioral changes in Alzheimer disease are typically secondary to cognitive decline and memory loss, not primary psychiatric phenomena. They emerge gradually and are often rooted in the patient's confusion and misinterpretation of events. ### Psychiatric Symptoms in Alzheimer Disease The neuropsychiatric syndrome of Alzheimer disease (NPSAD) includes: | Symptom Category | Frequency | Characteristics | |---|---|---| | Delusions | 10–20% | Usually persecutory; arise from memory loss (e.g., "Where are my things?" → "Someone stole them") | | Hallucinations | 10–15% | Often visual; less common than delusions | | Behavioral disturbance | 20–30% | Irritability, agitation, apathy, wandering | | Mood symptoms | 20–40% | Depression, anxiety, emotional lability | | Apathy | 30–40% | Loss of motivation and social withdrawal | **Clinical Pearl:** Delusions in Alzheimer disease are **secondary delusions** — they arise from the patient's attempt to make sense of a confusing world created by cognitive decline. A patient who cannot remember where she put her keys may conclude that someone stole them. This is fundamentally different from primary delusions in schizophrenia, which arise without obvious external cause. **High-Yield:** The combination of **progressive memory loss + persecutory delusions + irritability + social withdrawal** is the classic neuropsychiatric triad of early-to-moderate Alzheimer disease. Apathy (loss of motivation) is one of the most common and disabling features. ### Why This Patient's Presentation Fits Alzheimer Disease 1. **Cognitive decline** (memory, language, visuospatial) documented on Mini-Cog and imaging 2. **Delusions** (accusations of theft) that are secondary to memory loss 3. **Behavioral changes** (irritability, suspiciousness) emerging in the context of dementia 4. **Apathy** (social withdrawal, loss of interest) 5. **Gradual onset** over 2 years — consistent with Alzheimer disease progression **Mnemonic:** ABCDE of Alzheimer neuropsychiatric features — **A**pathy, **B**ehavioral disturbance, **C**ognitive decline (primary), **D**elusions (secondary), **E**motional lability. [cite:Harrison 21e Ch 452]