Psychosis in behavioral variant frontotemporal dementia

Abstract

BackgroundDementia is generally characterized by cognitive impairment that can be accompanied by psychotic symptoms; for example, visual hallucinations are a core feature of dementia with Lewy bodies, and delusions are often seen in Alzheimer’s disease. However, for behavioral variant of frontotemporal dementia (bvFTD), studies on the broad spectrum of psychotic symptoms are still lacking. The aim of this study was to systematically and prospectively subtype the wide spectrum of psychotic symptoms in probable and definite bvFTD.MethodsIn this study, a commonly used and validated clinical scale that quantifies the broad spectrum of psychotic symptoms (Positive and Negative Symptom Scale) was used in patients with probable and definite bvFTD (n=22) and with a primary psychiatric disorder (n=35) in a late-onset frontal lobe cohort. Median symptom duration was 2.8 years, and the patients were prospectively followed for 2 years.ResultsIn total, 22.7% of bvFTD patients suffered from delusions, hallucinatory behavior, and suspiciousness, although the majority of the patients exhibited negative psychotic symptoms such as social and emotional withdrawal and blunted affect (95.5%) and formal thought disorders (81.8%). “Difficulty in abstract thinking” and “stereotypical thinking” (formal thought disorders) differentiated bvFTD from psychiatric disorders. The combined predictors difficulty in abstract thinking, stereotypical thinking, “anxiety”, “guilt feelings,” and “tension” explained 75.4% of variance in the diagnosis of bvFTD versus psychiatric diagnoses (P<0.001).ConclusionDelusions, hallucinatory behavior, and suspiciousness were present in one-fifth of bvFTD patients, whereas negative psychotic symptoms such as social and emotional withdrawal, blunted affect, and formal thought disorders were more frequently present. This suggests that negative psychotic symptoms and formal thought disorders have an important role in the psychiatric misdiagnosis in bvFTD; misdiagnosis in bvFTD might be reduced by systematically exploring the broad spectrum of psychiatric symptoms.

Frontotemporal Dementia: Correlations Between Psychiatric Symptoms and Pathology

“…According to current diagnostic criteria, a primary psychiatric diagnosis is still considered an exclusion criterion for FTD . On the contrary, our results and those of other recent studies suggest that including more neuropsychiatric symptoms in the clinical assessment might improve diagnostic accuracy.…”

“…Mutations in genes, such as chromosome 9 open reading frame 72 ( C9orf72 ), progranulin ( GRN ), and microtubule associated protein tau ( MAPT ) have been identified in about 25% of patients with FTD . More recently, neuropsychiatric symptoms, such as psychosis and depressed mood, have been recognized to be part of the early clinical presentation of FTD, both in C9orf72 repeat expansion carriers and noncarriers . Due to the clinical variability and overlap of symptoms with primary psychiatric diseases and other neurodegenerative diseases, such as Alzheimer's disease, and given the lack of biomarkers, it remains challenging to diagnose FTD accurately in a clinical setting.…”

Neuropsychiatric Symptoms as Predictors of Clinical Course in Neurodegeneration. A Longitudinal Study

“…Previous studies have shown different neurocognitive progression according to the major type of symptom in FTD (Santamaría-García et al, 2016). A broad range of NPS in both AD and FTD has been described including delusions and sensory-perceptual alterations (hallucinations and illusions; Rubin et al, 1988; Van Dam et al, 2016; Gossink et al, 2017), as well as conduct problems (Santamaría-García et al, 2016; Van Dam et al, 2016), depressive and anxiety symptoms (Brodaty et al, 2015; Sellami et al, 2018), sleep problems (Mander et al, 2016; Merrilees et al, 2014) and eating changes (Ahmed et al, 2015; Ringman et al, 2015). Regarding the psychotic symptoms (including delusions and sensory-perceptive alterations such as hallucinations and illusions), previous studies have reported that those symptoms can appear in both AD and FTD.…”

Comparison of Prodromal Symptoms of Patients with Behavioral Variant Frontotemporal Dementia and Alzheimer Disease

“…In addition, particularly FTLD patients with a concomitant motor neuron disease have been observed to present with prominent psychotic symptoms in the prodromal stage of the disease [65,66]. Previous studies also indicate that up to one third of the bvFTD patients will develop psychotic symptoms at some stage of the disease [23,29,67]. Nevertheless, these symptoms are not part of the current diagnostic bvFTD criteria [2], and a significant number of bvFTD patients will receive a psychiatric diagnosis in the early stages of the disease [65,68].…”