{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T01:54:57Z","timestamp":1779933297735,"version":"3.53.1"},"reference-count":48,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2016,10,1]],"date-time":"2016-10-01T00:00:00Z","timestamp":1475280000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["movementdisorders.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Movement Disord Clin Pract"],"published-print":{"date-parts":[[2017,5]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background<\/jats:title><jats:p>Elevated levels of irritability are reported to occur in a number of neurological conditions, including Huntington's disease (<jats:styled-content style=\"fixed-case\">HD<\/jats:styled-content>), a genetic neurodegenerative disorder. Snaith's Irritability Scale (<jats:styled-content style=\"fixed-case\">SIS<\/jats:styled-content>) is used within <jats:styled-content style=\"fixed-case\">HD<\/jats:styled-content> 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 <jats:styled-content style=\"fixed-case\">HD<\/jats:styled-content> population.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Exploratory and confirmatory factor analysis were used to examine the structural properties of <jats:styled-content style=\"fixed-case\">SIS<\/jats:styled-content> using responses from 1,264 <jats:styled-content style=\"fixed-case\">HD<\/jats:styled-content> gene expansion carriers, across 15 European countries, who were engaged in the <jats:styled-content style=\"fixed-case\">REGISTRY<\/jats:styled-content> 3 study.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>An exploratory factor analysis of a subsample of the data suggested a two\u2010factor interpretation of the data comprising \u201ctemper\u201d and \u201cself\u2010harm.\u201d Eight possible models were tested for goodness of fit using confirmatory factor analysis. Two bifactor models, testing general and group factors in the structure of the scale, provided an equivocal \u201cgood\u201d fit to the data. The first comprised a general irritability factor and two group factors (as originally proposed using <jats:styled-content style=\"fixed-case\">SIS<\/jats:styled-content>): outward irritability and inward irritability. The second comprised a general irritability factor and two group factors (as proposed by the exploratory factor analysis): temper and self\u2010harm. The findings from both models suggested that the loadings of items were higher on the general factor.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Bifactor models are proposed to best consider the structure of the <jats:styled-content style=\"fixed-case\">SIS<\/jats:styled-content>, with findings suggesting that an overall score should be used to measure irritability within <jats:styled-content style=\"fixed-case\">HD<\/jats:styled-content> populations.<\/jats:p><\/jats:sec>","DOI":"10.1002\/mdc3.12424","type":"journal-article","created":{"date-parts":[[2016,7,28]],"date-time":"2016-07-28T03:46:38Z","timestamp":1469677598000},"page":"342-348","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Irritability in Huntington's Disease: Factor Analysis of Snaith's Irritability 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