Cognitive Deficits in Patients With Neuropsychiatric Symptoms: A Comparative Study Between Behavioral Variant Frontotemporal Dementia and Primary Psychiatric Disorders

Objective: To compare neuropsychological profiles in behavioral variant frontotemporal dementia (bvFTD) with its most common primary psychiatric differential diagnoses, major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia, in older patients with active symptoms.

Methods: We included patients from different cohorts with MDD (DSM-IV-TR: 296.20-296.23, 296.30-296.33; n = 42; mean ± SD age, 72.0 ± 8.0 years; female = 57.1%) included from 2002 to 2007, noneuthymic BD (DSM-IV-TR: 296.00-296.06, 296.40-296.46, 296.50-296.56, 296.60-296.66, 296.7; DSM-IV-TR: 296.89; DSM-IV-TR: 296.80; n = 41; age, 71.7 ± 8.8 years; female = 53.7%) included from 2011 to 2015, nonremitted schizophrenia (DSM-IV-TR: 295.10, 295.20, 295.30, 295.60, 295.90; n = 47; age, 67.5 ± 7.1 years; female = 66%) included from 2006 to 2008, or probable/definite bvFTD (n = 173; age, 62.6 ± 8.0 years; female = 39.9%) (Frontotemporal Dementia Consensus criteria) included from 2000 to 2015 and healthy controls (n = 78; age, 71.9 ± 8.0 years; female = 71.8%) included from 2005 to 2007. Neuropsychological tests concerned the domains of attention and working memory, verbal memory, verbal fluency, and executive functioning. Analyses of variance were performed with age, gender, and education level as covariates. Post hoc Bonferroni tests were used to detail group differences.

Results: Compared to the healthy controls, both the bvFTD and primary psychiatric disorder groups showed significant impairment on all cognitive domains. Executive function was more disturbed in all primary psychiatric disorders compared to bvFTD (P < .001). Attention and working memory were significantly better in the bvFTD and schizophrenia groups compared to the MDD and BD groups (P < .001). For verbal memory, the bvFTD group scored significantly higher compared to patients with schizophrenia, BD, or MDD (P < .001). Patients with bvFTD had significantly lower scores on verbal fluency, especially due to Animal Naming, in comparison with the BD group (P < .001); however, these scores were not significantly different from those of MDD or schizophrenia patients.

Conclusions: Cognitive deficits in bvFTD are less severe than in primary psychiatric disorders with active symptoms. This indicates that in the differential diagnosis of bvFTD, disturbances on tests for cognitive performance do not rule out primary psychiatric diagnoses.