Since California became the first state to legalize medical marijuana in 1996, every couple of years, another state or two are added to the list (there were five in 2016). It is inevitable that the medical use of marijuana will eventually be legal in all 50 states.
The effectiveness of medical marijuana has been debated ever since the residents of California started the ball rolling by approving a ballot proposition to legalize it. Proponents of medical marijuana generally tout its effectiveness in treating nausea, loss of appetite, inflammation, chronic pain, seizures, spasms, depression, insomnia, and anxiety. Opponents of medical marijuana tend to downplay or deny altogether its effectiveness. Both sides regularly seize upon medical studies that support their respective positions.
According to a recent study published in Frontiers in Pain Research in May of 2022 ("The Effectiveness and Safety of Medical Cannabis for Treating Cancer Related Symptoms in Oncology Patients"):
The use of medical cannabis (MC) to treat cancer-related symptoms is rising. However, there is a lack of long-term trials to assess the benefits and safety of MC treatment in this population. In this work, we followed up prospectively and longitudinally on the effectiveness and safety of MC treatment.
Most outcome measures improved significantly during MC treatment for most patients.