• Published: September 6, 2023
• https://doi.org/10.1371/journal.pone.0290549

Aims

In Australia, individuals suffering from chronic health conditions, which do not seem to respond to standard forms of treatment, now have the option to access medicinal cannabis (MC) through valid prescriptions provided by medical practitioners. This alternative form of treatment, which once was only accessible through specific channels or in certain regions, now brings hope to patients across the country experiencing chronic conditions. With the proliferation of medicinal cannabis, we aimed to study the various effects it may have on these patients, particularly in relation to their overall health-related quality of life (HRQL). This study’s primary objective was to analyze and assess the overall health-related quality of life in a broad, real-world sample of patients who have been prescribed medicinal cannabis. It is critical to understand how medicinal cannabis influences HRQL, as it can provide a comprehensive picture of a patient’s well-being, capturing the physical, psychological, and social domains of health. Many patients with chronic illnesses suffer a lower HRQL, and if medicinal cannabis can improve this, it could hold significant implications for future treatment strategies. In addition to the HRQL, we also aimed to measure the impact of medicinal cannabis on various other aspects that directly influence the quality of life for patients. These included pain, fatigue, sleep, anxiety, and depression. Chronic pain and fatigue are two of the most debilitating symptoms that patients with chronic conditions often face. These symptoms can negatively affect all aspects of a person’s life, including their ability to work, socialize, and perform daily tasks. Therefore, understanding the effects of medicinal cannabis on these symptoms could provide critical insights into its potential therapeutic benefits. Sleep disturbances are also common among individuals suffering from chronic health conditions, which can further exacerbate the severity of other symptoms and negatively affect the overall quality of life. As such, we aimed to investigate the impact of medicinal cannabis on sleep patterns among the sample population. Similarly, anxiety and depression are prevalent mental health conditions found in patients with chronic illnesses. These mental health conditions can significantly affect patients’ quality of life and can also contribute to the worsening of physical symptoms. Therefore, we sought to explore the impact of medicinal cannabis on symptoms of anxiety and depression. Our hypothesis was that all the patient-reported outcomes (PROs)—from the overall health quality to the specific aspects mentioned above—would demonstrate an improvement from baseline to the 3-month mark following the commencement of medicinal cannabis treatment. We believed that this particular treatment approach could potentially offer an effective solution to manage the symptoms associated with chronic health conditions. In other words, we postulated that medicinal cannabis could significantly enhance overall well-being and improve the quality of life for patients dealing with chronic health conditions. This research could provide valuable insights and contribute to the expanding body of knowledge surrounding medicinal cannabis use and its effects on patients. Our aim was not only to verify the efficacy of medicinal cannabis but also to provide reliable, empirical data that could potentially shape future healthcare policies and treatment strategies.

Methods

The Quality Examination of Understanding Short-Term Outcomes with Medicinal Cannabis Therapy (QUEST) Initiative is a large, ambitious and comprehensive prospective multicenter study established to examine patients suffering from any chronic health condition. These patients were newly prescribed medicinal cannabis between November 2020 and December 2021. The study, propelled by a commitment to rigorous scientific investigation, is emblematic of an emerging trend in medical research seeking to understand the potential benefits and risks associated with the therapeutic usage of cannabis. The study’s population was composed of eligible patients identified by a network of 120 clinicians working at medical centers spread across six Australian states. These states included New South Wales, Victoria, Queensland, South Australia, Western Australia, and Tasmania. The team of clinicians was dedicated and diverse, comprising general practitioners, specialists, and nurse practitioners who had well-established relationships with their patients, ensuring a high level of trust and communication. Before starting therapy, consenting participants completed a range of carefully selected questionnaires aimed at capturing a comprehensive picture of their health status and quality of life. The questionnaires were administered at various stages of the study, including prior to the initiation of therapy, at the 2-weeks titration period, and then on a monthly basis for the subsequent 3-months. This systematic approach allowed for a detailed and dynamic understanding of the impact of medicinal cannabis on the patients’ health over time. The questionnaires used in the study included the EuroQol Group EQ-5D-5L health status questionnaire, a widely respected instrument designed to provide a simple, generic measure of health for clinical and economic appraisal. This questionnaire assesses patients’ self-perception of their health status across five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Beyond the EuroQol Group questionnaire, participants also completed the European Organization for Research & Treatment of Cancer Quality of Life questionnaire, known as the EORTC QLQ-C30. This specific instrument has been developed to assess the quality of life of cancer patients, focusing on issues such as physical functioning, role functioning, emotional functioning, cognitive functioning, and social functioning. Further complementing these data collection tools were the Patient-Reported Outcomes Measurement Information System (PROMIS) Short Forms in Fatigue and Sleep Disturbance, as well as the Depression Anxiety Stress Scale (DASS-21). The PROMIS assessments were implemented to gauge the patients’ levels of fatigue and sleep disturbance, two common symptoms often associated with chronic health conditions. Similarly, the DASS-21 served to help the study capture evidence-based measures of depression, anxiety, and stress, thereby providing a comprehensive mental health profile of the participants before and after the administration of medicinal cannabis. In conclusion, the QUEST Initiative is an expansive scientific endeavor aiming to contribute to the growing body of knowledge surrounding medicinal cannabis. By meticulously tracking patients’ experiences over time, the study hopes to provide invaluable insights that could ultimately shape future practices and policies related to medicinal cannabis usage.

Results

The study in question involved the voluntary participation of 2762 individuals. The demographic of participant ages was broad, with the youngest participant at the threshold of adulthood at 18, and the eldest participant nearing a century at 97 years old. The average age of the participants, or the mean, was 51 years. The standard deviation, a regularly used statistical tool that measures the dispersion of values within a data set, was 15.4 years. This data suggests a wide-ranging age group, a factor that was intentional to enable a more comprehensive understanding and representation of the plethora of issues faced by different age demographics in relation to the study’s focus. Taking into consideration the gender distribution among participants, females significantly dominated, making up precisely 62.8% of the total. This majority of female participants serves to highlight their readiness to actively engage in such surveys, thereby contributing significantly to the collective understanding of the health-related quality of life (HRQL), a measure of the impact of health status on quality of life. The study also collated information about the conditions the participants were being treated for. Chronic pain emerged as the most recurrent, plaguing 1598 out of the 2327 participants who successfully completed the survey. This substantial segment of participants corresponds to 68.7% of the group. Following chronic pain, insomnia ranked the second most common condition, affecting 534 participants, or 22.9% of the total. Generalized anxiety was another notable condition, reported by 21.5% of the respondents, which equates to 508 individuals. Mixed anxiety and depression were observed in 259 participants, making up 11% of the total. These data points were collected across the entire group of participants. Two paramount indicators of HRQL used in this study were the EQ-5D-5L utility scores and QLQ-C30 summary scores. Both demonstrated a clinically significant improvement from the initial baseline to the average follow-up. The effect size ‘d’, which is a measure of the magnitude of an intervention’s effect, was 0.54 for EQ-5D-5L utility scores, with a 95% confidence interval ranging from 0.47 to 0.59. For QLQ-C30 summary scores, ‘d’ was 0.64, with the confidence interval ranging from 0.58 to 0.70. These results imply a significant enhancement in the HRQL following the interventions introduced in the study. Another remarkable discovery was the clinically significant improvement in fatigue levels. This condition is often reported in chronic illnesses. The recorded effect size for fatigue was 0.54, with a 95% confidence interval from 0.48 to 0.59, indicating successful management of this often debilitating symptom. Within the sub-group of participants enduring chronic pain, there was a clinically meaningful reduction in their pain levels. The effect size for these individuals was 0.65, with a 95% confidence interval from 0.57 to 0.72. Furthermore, participants suffering from moderate to extremely severe anxiety and depression showed significant improvements over the course of the study. This was demonstrated in the chi-square statistics, a statistical test applied to groups of categorical data to evaluate how likely it is that any observed difference arose by chance. The chi-square value for anxiety was 383, with degrees of freedom equal to 4 and a p-value less than 0.001. The same parameters applied for depression, with a chi-square value of 395. This data suggests a notable improvement in mental health conditions among participants. However, despite numerous achievements, no significant alterations were observed in sleep disturbances among the participants. This implies that the interventions applied in this study were ineffective in addressing sleep-related issues. Therefore, it highlights an area for potential future research to explore mechanisms that could manage sleep disturbances more effectively.

Conclusions

In our research, we conducted an intensive observation and discovered remarkable results. We found that there were statistically significant and clinically meaningful improvements in the overall Health-Related Quality of Life (HRQL) and fatigue reduction over the initial 3-month period. This was particularly true in patients struggling with various chronic health conditions who were accessing prescribed medical cannabis as part of their ongoing treatment plan. The Health-Related Quality of Life is a multi-dimensional concept that includes domains related to physical, mental, emotional, and social functioning. It goes beyond direct measures of population health, life expectancy, and causes of death, and focuses on the impact health status has on quality of life. In this regard, we noticed a marked improvement in the overall wellbeing of these patients, suggesting that medical cannabis played a considerable role in their improved HRQL. The most notable changes were evident in fatigue levels. Fatigue, a common symptom associated with chronic conditions, often presents a considerable challenge for patients. It can affect every aspect of their life, from work performance to personal relationships. However, in this specific study, we observed considerable reductions in exhaustion levels. This enhanced energy state has profound implications, as it can radically improve patients’ productivity, engagement in social activities, and overall contentment with life. In addition to these significant improvements, we also noticed that anxiety, depression, and pain levels showed a marked reduction over time. These improvements were particularly pronounced for those patients whose chronic health conditions included these symptoms. It is worth noting that conditions such as anxiety, depression, and chronic pain can often be debilitating and limit patients’ ability to lead fulfilled lives. The alleviation of these symptoms through the use of medical cannabis has profound implications, potentially enabling a higher quality of life for those suffering from such conditions. The study did not merely end at these observations. It continues to monitor and follow-up with these patients for a total duration of 12-months. This extended period allows us to determine whether these significant improvements in Patient-Reported Outcomes (PROs) are maintained long-term. PROs provide valuable insights into a patient’s health state, disease burden, and the effects of treatment, that cannot be captured from a clinician’s perspective. This information is fundamental as it gives us a clearer understanding of how medical cannabis impacts patients’ lives beyond mere symptom control. In conclusion, this study aims to contribute valuable data to the ongoing discussions about the potential benefits of prescribed medical cannabis. The initial findings have been encouraging, showing significant improvements in health-related quality of life, fatigue, anxiety, depression, and pain among patients with chronic health conditions. The continued follow-up will help to determine whether these benefits are sustained over the long term.

Trail registration

Study registration – Australian New Zealand Clinical Trials Registry: ACTRN12621000063819. https://www.australianclinicaltrials.gov.au/anzctr/trial/ACTRN12621000063819.