Landmark Review Finds No Evidence of Medicinal Cannabis Efficacy for Major Mental Health Disorders
核心洞察
A comprehensive Lancet Psychiatry review of 54 randomized controlled trials involving 2,477 participants found no evidence that medicinal cannabis (搜索) effectively treats anxiety (搜索), depression (搜索), or PTSD (搜索).
The study raises concerns about the rapid expansion of cannabinoid prescriptions, with over one million approvals in Australia over four years despite insufficient evidence for mental health applications.
While some limited benefits were observed for Tourette's syndrome (搜索) tics and cannabis-use disorder (搜索) withdrawal symptoms, the overall quality of evidence remains low for most conditions.
The largest-ever systematic review examining medicinal cannabis (搜索) for mental health conditions has found no evidence supporting its effectiveness in treating anxiety (搜索), depression (搜索), or post-traumatic stress disorder (PTSD (搜索)), according to research published in The Lancet Psychiatry. The comprehensive analysis, spanning 45 years of clinical data, challenges the growing use of cannabinoid medications for psychiatric disorders.
Dr. Jack Wilson from the University of Sydney's The Matilda Centre (搜索) led the landmark study, which analyzed 54 randomized controlled trials conducted between 1980 and 2025, involving 2,477 participants across various mental health and substance-use disorders.
Questioning Current Prescribing Practices
The findings come amid explosive growth in medicinal cannabis (搜索) use, with Australia experiencing more than one million prescription approvals and a tripling of cannabinoid medication sales over the past four years. More than 700,000 Australians have reported using medicinal cannabis to treat over 250 different health conditions, often for mental health disorders.
"The results call into question the approval of medicinal cannabis (搜索) for the treatment of depression (搜索), anxiety (搜索) and PTSD (搜索)," Wilson stated. "Though our paper didn't specifically look at this, the routine use of medicinal cannabis could be doing more harm than good by worsening mental health outcomes, for example a greater risk of psychotic symptoms and developing cannabis use disorder, and delaying the use of more effective treatments."
Limited Evidence for Select Conditions
While the review found insufficient evidence for major mental health disorders, researchers identified potential benefits for specific conditions. Medicinal cannabis (搜索) showed some promise in reducing tic severity in Tourette's syndrome (搜索) and addressing withdrawal symptoms in cannabis-use disorder (搜索).
"Similar to how methadone is used to treat opioid-use disorder, cannabis medicines may form part of an effective treatment for those with a cannabis-use disorder (搜索)," Wilson explained. "When administered alongside psychological therapy, an oral formulation of cannabis was shown to reduce cannabis smoking."
The study also found evidence suggesting potential benefits for autism (搜索), insomnia (搜索), and certain neurological conditions. However, Wilson cautioned that "the overall quality of evidence for these other conditions, such as autism and insomnia, was low. In the absence of robust medical or counselling support, the use of medicinal cannabis (搜索) in these cases are rarely justified."
Concerning Findings for Substance Abuse
The research revealed troubling results for certain substance-use disorders. While medicinal cannabis (搜索) may help with cannabis dependence, it was found to increase cocaine cravings among people with cocaine-use disorder (搜索).
"When medicinal cannabis (搜索) was used to treat people with cocaine-use disorder (搜索), it increased their cravings," Wilson noted. "This means it should not be considered for this purpose and may, in fact, worsen cocaine dependence."
Regulatory Implications
The rapid expansion in medicinal cannabis (搜索) prescribing has raised concerns among major medical bodies, including the Australian Medical Association (搜索) and the Pharmacy Guild of Australia (搜索), about largely unregulated growth and uncertainty surrounding product efficacy and safety.
In response to these concerns, the Therapeutic Goods Administration (搜索) initiated a review of medicinal cannabis (搜索) regulatory oversight, receiving more than 500 responses published in February.
"Our study provides a comprehensive and independent assessment of the benefits and risks of cannabis medicines, which may support the TGA and clinicians to make evidence-based decisions, helping to ensure patients receive effective treatments while minimising harm from ineffective or unsafe cannabis products," Wilson concluded.
The researchers emphasized that while medicinal cannabis (搜索) has demonstrated efficacy for certain conditions such as reducing seizures in some forms of epilepsy (搜索), managing spasticity in multiple sclerosis (搜索), and treating specific types of pain, the evidence for mental health disorders falls significantly short of supporting widespread clinical use.