Psychiatric patients in a day-center and alcoholics experienced a lower health-related quality of life (HRQOL) in most respects, with the exception of pain and physical health, than did physically disabled persons, who in turn rated their quality of life to be considerably below that for those visiting general practitioners. These results are based on a study using a 30-item questionnaire IQL (Icelandic Quality of Life) constructed by selecting the best items from seven other questionnaires using hierarchical cluster analysis for separating 11 aspects of quality of life, and a detailed quantitative and qualitative item analysis. The IQL has acceptable reliability and validity; however, to distinguish between the disabled and the alcoholic's quality of life, profiles on the basis of the above-mentioned aspects should be used rather than one summary score. An exploratory principal component analysis indicated that four factors explained 68% of the Variance found in the health-related quality of life of participants in the study. One of these factors explains nearly half of the observed variance. Items loading high on that factor are all related to mental health. The other factors include items on physical health and specific items on sleep and financial status.
