CONVERGENT NEURAL SUBSTRATES UNDERLYING ANHEDONIA AND COMPULSIVE EATING IN FRONTOTEMPORAL DEMENTIA

Frontotemporal dementia (FTD) is characterised by marked motivational disturbances, including compulsive eating and loss of pleasure (anhedonia). Although typically examined in isolation, the co-occurrence of these symptoms suggests disruption of a shared underlying neural mechanism. This study aimed to investigate behavioural and neuroanatomical links between anhedonia and eating disturbances in FTD. One hundred and seventeen individuals with FTD (behavioural-variant FTD, n = 84; semantic dementia, n = 33) were compared with 27 healthy controls on the Snaith–Hamilton Pleasure Scale and the Cambridge Behavioural Inventory–Revised Eating subscale. Group differences were examined using analyses of variance, and associations between anhedonia and eating disturbances were assessed using Spearman correlations. Voxel-based morphometry analyses identified grey matter correlates of behavioural measures, controlling for age, sex, education, scanning site, and total intracranial volume. Relative to controls, both patient groups exhibited significantly greater anhedonia and eating disturbances (all p's < .001), with eating disturbances more pronounced in behavioural-variant FTD than semantic dementia (p < .001). Across the FTD cohort, greater anhedonia was associated with more severe eating disturbances (r = −0.20, p = .032). Anhedonia correlated with atrophy in a predominantly right-lateralised network including the Rolandic operculum, supplementary motor area, and cerebellum. Eating disturbances showed overlapping involvement of the Rolandic operculum and supplementary motor area, with additional orbitofrontal and thalamic contributions. In conclusion, these findings demonstrate convergent behavioural and neuroanatomical substrates linking loss of pleasure and compulsive eating in FTD, indicating a shared disruption of neural systems governing hedonic valuation and motivated action.