The ISI uses a Likert scale ranging from 0 to 4 for each of its seven items, with total scores ranging from 0 to 28. The score interpretation is as follows:
0-7: No clinically significant insomnia 8-14: Subthreshold insomnia 15-21: Moderate insomnia 22-28: Severe insomnia
Higher scores indicate greater insomnia severity. This scoring system helps in categorizing the severity of insomnia and guiding treatment decisions.
