Management of catatonia in Huntington disease: A scoping review.

INTRODUCTION: Huntington disease (HD) is a progressive neurodegenerative disorder caused by CAG repeat expansion in the HTT gene. It typically presents with choreiform movements, cognitive decline, and executive dysfunction. Moreover, psychiatric symptoms such as depression, psychosis, and disinhibition are common. Catatonia, a rare and mostly unstudied comorbidity of HD, presents with mutism, rigidity, and agitation. Overlapping psychomotor and behavioral features make the diagnosis of HD with concomitant catatonia challenging. We conducted a scoping review to examine reported cases of catatonia in HD, focusing on diagnostic challenges, treatment approaches, and outcomes.

METHODS: A systematic literature search was conducted across PubMed, PubMed Central, Scopus, Embase, Web of Science, and APA PsycInfo using MeSH terms "Huntington Disease" and "Catatonia." We also included additional free text search terms combining "Huntington" and "catatonia OR catatonic OR catalepsy OR mutism OR stupor OR rigidity OR waxy flexibility OR Bush Francis". Peer-reviewed studies reporting confirmed or probable HD with catatonia were included. Three articles describing four unique cases met the inclusion criteria.

RESULTS: Four cases of catatonia in HD were identified (ages 16-62). Presentations ranged from excited to stuporous catatonia, often with psychosis or mood disorders. All received lorazepam with variable responses. Electroconvulsive therapy (ECT) was administered in all four cases, yielding partial or complete relief in most, though one required maintenance ECT and another worsened. Antipsychotics were inconsistently used and sometimes exacerbated symptoms. From the cases reviewed, recurrence was frequently observed with subsequent remission after additional ECT courses.

DISCUSSION: Catatonia in HD is rare and difficult to diagnose due to overlapping motor and behavioral symptoms. Psychosis was present in all reviewed cases, indicating a potential association worthy of future investigation. While lorazepam is typically first-line, ECT showed the most consistent benefit, though relapses were frequent. Moreover, there is evidence to suggest that antipsychotics with strong dopamine antagonism should be used cautiously in this patient population.

CONCLUSION: This review highlights the rarity and complexity of catatonia in HD and underscores the need for greater clinical awareness. ECT appears effective for many patients, but individualized treatment plans are essential. Further research is needed to clarify diagnostic criteria, underlying mechanisms, and long-term management strategies.