Quality of life is an integral element of a new perspective on health. Even though the definition and structure of the concept of quality of life are still being debated, researchers exploring the topic agree that it has both objective and subjective dimensions. When the quality of life of patients is examined somatically, the objectives formulated in the study procedure are usually easily achieved, particularly when the basic hypothesis is that good physical health generates a high quality of life. However, where mental diseases and dysfunctions are investigated, and the analysis involves a large number of variables constituting quality of life, the relationship is not so clear-cut. Consequently, in addition to methodological accuracy the researcher must put a major focus on the patients and their manifestations. The thesis stating that it is impossible to measure quality of life in this population, or worse still, that there is no need for such measurements, is indefensible, considering that people with mental disorders have the same right to a good life as healthy individuals, and achieving an improvement in their quality of life becomes an increasingly common target among anticipated therapeutic benefits. Looking at the issue from the perspective of findings obtained in multiple studies, it is evident that quality-of-life measurements are not easy, but a successful attempt may provide researchers with a source of valuable non-clinical data and even enhance their personal satisfaction.