The structure of mental health symptoms in Huntington’s disease: Comparisons with healthy populations

Abstract

ABSTRACT Introduction Mental health difficulties are common among people with Huntington’s disease (HD). However, such difficulties are only weakly associated with HD progression, suggesting their causes may be multifactorial rather than purely disease-related. Genetically unaffected family members have been shown to experience similar levels of mental distress to people with HD, potentially due to systemic stressors and life disruption. These factors may also influence mental wellbeing in people with HD. Accordingly, this study aimed to compare patterns and occurrence of mental distress between people with HD and genetically unaffected control groups, to determine systemic and environmental contributions to HD-related distress. Method Exploratory and confirmatory factor analysis was used to compare the structure of mental distress in 5,294 individuals from four groups: manifest or premanifest HD, family control, and genotype-negative. Data were from the Enroll-HD study, using scores from the Problem Behaviors Assessment, the Hospital Anxiety and Depression Scale, and the Snaith Irritability Scale. We then evaluated consistency of the identified constructs over three annual assessments using analysis of variance. Results Four factors consistently emerged across all groups, comprising depression, anxiety, temper and self-harm; these remained stable across time. People with HD did not report significantly different anxiety scores to control groups. The manifest group reported significantly higher depression, temper and self-harm than the genotype-negative group, but only differed in some cases from family-controls. Conclusions The findings suggest greater similarity in the severity and structure of mental health symptoms between people with and without HD than previously believed. This suggests contributions from systemic as well as genetic factors in families affected by HD, especially in terms of anxiety symptoms.