Psychosis in behavioral variant frontotemporal dementia.

Area of Science:

• Neuroscience
• Psychiatry
• Clinical Neurology

Background:

• Dementia, including Lewy body dementia and Alzheimer's disease, often involves psychotic symptoms.
• Psychotic symptom spectrum in behavioral variant frontotemporal dementia (bvFTD) remains understudied.
• bvFTD diagnosis can be challenging due to overlapping symptoms with psychiatric disorders.

Purpose of the Study:

• To systematically and prospectively subtype the broad spectrum of psychotic symptoms in probable and definite bvFTD.
• To differentiate psychotic symptom profiles between bvFTD and primary psychiatric disorders.
• To identify clinical features that aid in distinguishing bvFTD from psychiatric conditions.

Main Methods:

• Utilized the Positive and Negative Symptom Scale to assess psychotic symptoms in patients with probable/definite bvFTD (n=22) and primary psychiatric disorders (n=35).
• Included patients from a late-onset frontal lobe cohort with a median symptom duration of 2.8 years.
• Conducted a prospective follow-up of patients over 2 years.

Main Results:

• 22.7% of bvFTD patients exhibited delusions, hallucinatory behavior, or suspiciousness.
• The majority of bvFTD patients presented with negative psychotic symptoms (95.5%), including social/emotional withdrawal and blunted affect, and formal thought disorders (81.8%).
• Difficulty in abstract thinking and stereotypical thinking were key differentiators for bvFTD versus psychiatric disorders, alongside anxiety, guilt, and tension, explaining 75.4% of diagnostic variance (P<0.001).

Conclusions:

• Negative psychotic symptoms and formal thought disorders are more prevalent in bvFTD than positive psychotic symptoms.
• These findings highlight the role of negative psychotic symptoms and formal thought disorders in the potential psychiatric misdiagnosis of bvFTD.
• Systematic assessment of the full spectrum of psychiatric symptoms is crucial for reducing misdiagnosis in bvFTD.