RESUMEN
Dementia, particularly Alzheimer's disease, affects millions globally, with its prevalence increasing notably with age. Early-onset Alzheimer's disease, however, affects individuals under 65 years old. Unfortunately, diagnosing dementia in patients under 65 years old is quite challenging and is often delayed, missed, or wrong. Thus, we present the case of a 60-year-old female, with a medical history of hypothyroidism and presumed dementia on donepezil, who presented to the emergency department for agitation, dramatic change in personality and behavior, as well as cognitive decline that started in her late 50s. We discuss the importance of performing a thorough history and physical examination, as well as a comprehensive workup for patients who present with dramatic changes in behavior due to the wide range of potential diagnoses. While certain reversible causes, such as hypothyroidism, nutritional deficiencies, and polypharmacy, can be promptly identified and treated, chronic neurocognitive disorders such as Alzheimer's disease demand a timely evaluation for early multidisciplinary treatment to enhance patient outcomes.