The Insomnia Severity Index

The Insomnia Severity Index is a 7-item, self-report questionnaire used to assess the severity, nature, and impact of insomnia over the past two weeks. It measures insomnia, sleep satisfaction, daytime functioning impairment, and distress, with a total score ranging from 0 to 28, where higher scores indicate greater insomnia severity. The ISI is a reliable tool for screening for insomnia and monitoring treatment response.