Quality of life (QoL)

Quality of life is a person's overall sense of well-being and ability to take part in daily life, measured in health care through standardized questionnaires rather than by laboratory tests.

Health-related quality of life covers physical function, pain, energy, sleep, mood, social participation and the ability to work or care for oneself. It is captured with instruments such as the SF-36, the EQ-5D and condition-specific questionnaires, which assign scores that can be compared over time or between groups. Because the score reflects the individual's own judgment, two people with the same disease can report very different quality of life, and a change in score can be meaningful even when clinical markers stay the same.

Quality of life is a common secondary outcome in trials of treatments for chronic pain, epilepsy, cancer and mental health conditions, and regulators increasingly ask for it alongside primary outcomes. In veterinary medicine, owners complete validated scales that rate a pet's appetite, mobility, comfort and enjoyment, which guide decisions in chronic disease and end-of-life care. Cannabinoid trials in people and dogs have included quality-of-life measures, with early and mixed results.