When neurodegenerative disease masquerades as psychiatric illness: A clinical case study of early-onset frontotemporal dementia

Behavioral variant frontotemporal dementia is characterized by significant changes in personality and behavior with typical age of onset between the fifth and sixth decade of life. The following case study describes a 44-year-old female patient with a significant psychiatric history and distant mild traumatic brain injury who began to behaviorally decompensate in her mid-to-late 30s. She was referred for neuropsychological evaluation due to report of memory problems and progressive neuropsychiatric and neurobehavioral decline. Neuropsychological testing revealed diffuse cognitive impairment mediated by pronounced neurobehavioral executive dysfunction. Laboratory and genetic testing were unremarkable. Neuroimaging revealed statistically significant asymmetric hypometabolism in the bilateral frontotemporal region, more pronounced on the left. Taken together, results were suggestive of a primary underlying frontotemporal lobar degenerative process with secondary exacerbation due to chronic psychiatric distress. This case report highlights the importance of thorough differential diagnosis of a neurodegenerative process in a young adult with an overlay of longstanding psychiatric illness, especially when the etiology in question falls outside the typical age of onset.