Emotion regulation difficulties are selectively associated with executive and behavioural apathy in Huntington's...

Apathy occurs frequently in psychiatric and neurological disorders and is associated with functional impairment, reduced quality of life, and caregiver burden. Its underlying mechanisms are incompletely understood, but recent studies indicate that apathy is multidimensional and has heterogeneous manifestations across disorders. Self-regulatory processes, such as emotion regulation, may contribute to these manifestations, but this relationship has received little attention. Huntington's disease (HD) provides a clinical model for examining whether emotion regulation difficulties are associated with global and multidimensional apathy.

Eighty-nine HD gene expansion carriers (HDGECs) completed the Difficulties in Emotion Regulation Scale, Lille Apathy Rating Scale, and Dimensional Apathy Scale. Cognitive screening included the Montreal Cognitive Assessment and depressive symptoms were assessed with the Hamilton Depression Rating Scale. Hierarchical regressions examined associations between emotion regulation difficulties and apathy, adjusting for depressive symptoms.

Greater emotion regulation difficulties were associated with global, Executive, and Behaviour/Initiation apathy, but not Emotional apathy. After accounting for depressive symptoms, Executive and Behaviour/Initiation apathy explained an additional 24.2% of variance in emotion regulation difficulties, whereas global apathy explained an additional 5.8%. Exploratory subgroup analyses found an independent association between Executive apathy and emotion regulation difficulties in premanifest but not manifest HDGECs.

Emotion regulation difficulties were associated with global apathy and showed the strongest associations with Executive and Behaviour/Initiation apathy, independent of depressive symptoms. These findings suggest that self-regulatory processes may be relevant to the heterogeneous manifestations of apathy and highlight the importance of examining specific apathy dimensions when investigating its underlying mechanisms and informing potential treatment approaches.