Trouble managing emotions tracks with apathy in Huntington’s disease gene carriers

People who carry the genetic mutation for Huntington’s disease report more trouble controlling their emotions when they also struggle with apathy — and the link is strongest not with the emotional, withdrawn face of apathy, but with its executive and behavioural sides: the inability to plan, organize and get moving. That is the central finding of a cross-sectional study from the Danish Dementia Research Centre at Rigshospitalet, published in the Journal of Neurology, which is among the first to ask whether emotion regulation, a core self-regulatory skill, is tied to specific dimensions of apathy in this population.

Apathy — a reduction in goal-directed behaviour, cognition and emotion — is one of the most common and disabling symptoms across neurodegenerative disease, with prevalence estimates in different disorders ranging from 17 to 100 percent depending on the condition and how it is measured. It drives functional decline, erodes quality of life and burdens caregivers, yet its mechanisms remain poorly characterized. Growing evidence suggests apathy is not one thing: it comprises partially distinct cognitive, behavioural and emotional components, and different dimensions dominate in different diseases. Executive dysfunction and impaired initiation of action tend to mark movement disorders, while emotional blunting is particularly prominent in frontotemporal dementia.

The research team, led by Emilie Poulsen and Asmus Vogel, reasoned that one candidate mechanism sitting underneath several of these dimensions might be self-regulation more broadly — the mental machinery that monitors, evaluates and adjusts our responses to meet situational demands. Emotion regulation is one component of that machinery, and difficulties with it are consistently implicated in mental health problems. Huntington’s disease offered a clean test case: the disorder is caused by a single autosomal dominant mutation, apathy occurs at every stage, and previous work had already flagged executive and initiation deficits, as well as overlap between apathy and impulsivity, hinting at shared disturbances in goal-directed behaviour.

Between November 2023 and May 2025, the researchers recruited 94 Huntington’s disease gene expansion carriers through routine clinical follow-up at their neurogenetics clinic; five were excluded for missing data, leaving 89 participants — 48 premanifest and 41 manifest — with a mean age of 49.7 years. All had undergone genetic counselling and status disclosure. Participants completed the 36-item Difficulties in Emotion Regulation Scale, the Lille Apathy Rating Scale interview for global apathy, and the Dimensional Apathy Scale, which separates Executive apathy (planning, organization, attention), Behavioural/Cognitive Initiation apathy (reduced self-generation of ideas and action) and Emotional apathy (reduced emotional processing and expression). Clinicians rated depression with the Hamilton Depression Scale, and motor scores on the Unified Huntington’s Disease Rating Scale split participants into disease stages.

The correlations were striking in their selectivity. Emotion regulation difficulties correlated at rs = 0.60 with Executive apathy and rs = 0.55 with Behaviour/Initiation apathy, both surviving Holm–Bonferroni correction, while global apathy on the Lille scale came in at rs = 0.39. Emotional apathy showed no significant association at all (rs = 0.22, p = 0.068). Neither age nor cumulative genetic disease burden, estimated by CAP score, correlated with emotion regulation difficulties — the relationship was with the apathy dimensions, not with how far the underlying disease had progressed.

Because depression overlaps heavily with both apathy and emotion regulation, the team then used hierarchical regression, entering depressive symptoms first. Depression alone explained 36.0 percent of the variance in emotion regulation difficulties. Adding the Lille global apathy score contributed a further 5.8 percent. But when the two Dimensional Apathy Scale subtypes — Executive and Behaviour/Initiation — were entered instead, they explained an additional 24.2 percent of variance beyond depression, with both remaining independently significant in the final model. In other words, the dimensional view of apathy revealed an association that the global score largely obscured.

An exploratory look at disease stage added a twist. In premanifest carriers — people carrying the mutation who do not yet show overt motor signs — Executive apathy remained independently associated with emotion regulation difficulties after depression was accounted for, with the apathy measures adding 33.3 percent of variance. In manifest carriers, the two apathy dimensions added 18.2 percent jointly, but neither survived as an independent predictor, likely because depressive symptoms, which explained 40.2 percent of variance in that group, crowded them out. The authors caution that these subgroup analyses were exploratory and almost certainly underpowered given the smaller sample sizes.

The selectivity is what makes the result mechanistically interesting. Executive and Behaviour/Initiation apathy capture failures of cognitive control and action initiation — planning, organizing, self-generating behaviour — and effective emotion regulation relies on those very processes of monitoring, evaluating and modifying responses. The authors suggest this shared cognitive-control substrate could explain why emotion regulation difficulties track those two dimensions and not Emotional apathy, which reflects disturbed emotional processing and expression instead. The finding also fits recent theoretical work proposing that apathy and impulsivity, long treated as opposites, may co-occur because both stem from impaired cost–benefit evaluation of goal-directed action, and with studies in Huntington’s disease showing that apathy and impulsivity dimensions cluster around a common goal-directedness component.

Clinically, the study reinforces an increasingly firm line of evidence that apathy is not simply masked depression. Antidepressant trials have generally shown limited benefit for apathy, whereas methylphenidate has demonstrated some benefit in Alzheimer’s disease, pointing toward treatments that target motivational processes rather than mood alone. If self-regulatory difficulty is one thread in the fabric of apathy — particularly its executive and behavioural forms — that could eventually suggest new targets, though the authors stress that whether training or otherwise targeting self-regulation helps apathy remains an open question, especially in Huntington’s disease where evidence for psychological intervention is very thin.

The caveats matter. Everything hinged on self-report: the emotion regulation scale measures perceived difficulty, not objectively measured regulatory capacity, and even the interview-based apathy rating largely reflects participants’ own perceptions. Insight into one’s own deficits is known to decline in Huntington’s disease, and the sample was only mildly affected, excluding later-stage patients who might have shown different patterns. The cross-sectional design cannot say whether poor emotion regulation contributes to apathy, apathy dampens perceived regulation, or both flow from a shared cause — only longitudinal work can untangle that. And because the study was conducted in Huntington’s disease, it remains unknown whether the same selective association holds in ALS, multiple sclerosis or Parkinson’s disease, where executive and initiation-related apathy also appear. As a first look at the question, though, it makes a clear case that apathy’s dimensions deserve to be studied separately — and that the machinery of self-regulation belongs on the list of suspects.

Subject of Research: Emotion regulation difficulties are selectively associated with executive and behavioural apathy in Huntington’s disease

Article Title: Emotion regulation difficulties are selectively associated with executive and behavioural apathy in Huntington’s disease

Article References: Poulsen, E., Ásbjörnsdóttir, B., Hjermind, L. E., Nielsen, J. E., & Vogel, A. (2026). Emotion regulation difficulties are selectively associated with executive and behavioural apathy in Huntington’s disease. Journal of Neurology, 273(11), Article 683. https://doi.org/10.1007/s00415-026-14214-0

Image Credits: AI Generated

DOI: 10.1007/s00415-026-14214-0

Keywords: Emotion, regulation, difficulties, selectively, associated, executive, behavioural, apathy, Huntington, disease, scientific research