Three-Month QUEST Study Links Prescribed Medicinal Cannabis With Better Quality of Life and Symptom Relief

A large Australian observational study found that adults with chronic health conditions reported better health-related quality of life and less fatigue after three months of prescribed medicinal cannabis. Participants with chronic pain, anxiety, or depressive conditions also reported improvements in symptoms linked to those diagnoses, while people treated for insomnia did not report better sleep.

The findings came from the QUEST Initiative study published in PLOS ONE in 2023. The prospective, multicenter study followed adults who had recently been prescribed medicinal cannabis oil in Australia. Of 2,762 people who consented, 2,327 completed the baseline assessment and at least one follow-up questionnaire. Participants were between 18 and 97 years old, with an average age of 51; 62.8% were women.

Chronic pain was the most common reason for treatment, affecting 68.7% of participants. Other frequently reported conditions included insomnia, generalized anxiety, and mixed anxiety and depression. More than half of the participants were being treated for multiple health conditions.

Participants completed validated questionnaires before beginning treatment, approximately two weeks later during dose titration, and monthly for three months. The surveys assessed overall health-related quality of life, pain, fatigue, sleep disturbance, anxiety, and depression.

Overall quality-of-life scores improved by an amount the researchers considered clinically meaningful, not merely statistically significant. Fatigue also declined by more than the study’s predefined threshold for a meaningful improvement. Among participants diagnosed with chronic pain, pain scores improved substantially compared with baseline.

The mental-health findings were more mixed. Across the full group, anxiety scores moved from the moderate range toward mild symptoms, but the average change did not reach the researchers’ threshold for clinical importance. Participants being treated for anxiety, however, experienced a larger improvement that did meet that threshold. Depression scores also improved overall, although the average change fell short of the threshold for a clinically meaningful difference. The subgroup receiving treatment for depressive conditions showed a larger improvement.

Sleep was the main outcome that did not improve. Participants prescribed medicinal cannabis for insomnia reported no meaningful change in sleep disturbance during the three-month follow-up.

These results do not show that medicinal cannabis caused the improvements. QUEST was a single-arm observational study with no untreated or placebo-control group. Participants knew they were starting medicinal cannabis, and expectations about its benefits may have influenced their responses. The results may also have been affected by attrition: between 28% and 40% of participants missed questionnaires at individual follow-up points, and people who continued in the study may have been more likely to find treatment helpful.

The study also examined only four medicinal cannabis oil products supplied by one manufacturer, so the findings cannot automatically be generalized to every cannabis formulation, dose, or method of administration.

A subsequent 12-month QUEST follow-up published in 2025 reported that improvements in quality of life, fatigue, and several condition-specific outcomes were generally maintained among participants who continued providing data. That analysis also faced substantial loss to follow-up: only 778 of the 2,353 participants included in the analysis completed the 12-month assessment.

In Australia, medicinal cannabis access remains regulated. The Therapeutic Goods Administration’s patient guidance says medicinal cannabis can be obtained from a pharmacy with a prescription, while many products remain unapproved therapeutic goods that require access through specific regulatory pathways.

Taken together, the QUEST findings suggest that prescribed medicinal cannabis may be associated with improvements in quality of life, fatigue, and some pain and mental-health symptoms in people with chronic conditions. Controlled trials are still needed to determine how much of those improvements is attributable to cannabis itself and which patients, products, and doses are most likely to benefit.