Irritability in Huntington's Disease: Factor Analysis of Snaith's Irritability Scale.

Background: Elevated levels of irritability are reported to occur in a number of neurological conditions, including Huntington's disease (HD), a genetic neurodegenerative disorder. Snaith's Irritability Scale (SIS) is used within HD research, but no psychometric evaluation of this instrument has previously been undertaken. Therefore, the current study aimed to analyze the factor structure of this scale among an HD population.