Objectives: This study aimed to gain a better understanding of behavioral abnormalities in Huntington disease (HD) and to develop a method for reliably assessing these changes.
Background: Behavioral changes are a central feature of HD and often cause considerable distress and difficulty to patients and their relatives. However, they have received little attention from research despite their prevalence and clinical significance.
Methods: One hundred thirty-four patients with HD were assessed using the Problem Behaviors Assessment for Huntington Disease (PBA-HD), an instrument for rating the presence, severity and frequency of behavioral abnormalities in HD.
Results: The findings confirm that behavioral problems are common among patients with HD. The most common symptoms were loss of energy and initiative, poor perseverance and quality of work, impaired judgment, poor self-care and emotional blunting. Affective symptoms such as depression, anxiety and irritability occurred in around half the patients studied. Psychotic symptoms (hallucinations and delusions) were rarely reported. Factor analysis distinguished three clusters of behavioral symptoms, which were interpreted respectively as reflecting Apathy, Depression and Irritability. The 'Apathy' factor was highly correlated with duration of illness, whereas no such relationship was observed for the 'Depression' and 'Irritability' factors.
Conclusions: The results suggest that certain behavioral changes are fundamental to the progression of HD, whereas others have a more complex relationship to the disease process. The findings have implications for the choice of behavioral measures used to evaluate efficacy of therapeutic interventions.