Amid rising global interest and legal reforms surrounding cannabis, recent research is painting a complex picture of its true effects on common health problems such as insomnia, chronic pain, and anxiety. A series of large-scale studies from Australia to the United States highlight encouraging long-term improvements in quality of life for patients with stubborn conditions, but also raise serious caution about potential mental health risks such as paranoia, psychosis, and increased risk of psychiatric disorders.
As Thai policymakers and families follow worldwide debates about cannabis regulation, these discoveries underscore the urgent need for balanced, evidence-based understanding—especially as Thailand maintains its controversial liberalization of cannabis laws. For Thai readers, the latest research brings both promising insights and new caution around cannabis’ therapeutic potential.
In April 2025, a major Australian study known as the QUEST initiative reported that patients prescribed medicinal cannabis for chronic conditions—such as pain, fatigue, insomnia, anxiety, and depression—experienced sustained improvements in their health-related quality of life (HRQL) over a full year. According to the 2,353 participants who completed follow-up assessments, benefits included not only reduced physical discomfort but also better sleep, decreased fatigue, and improvements in mental health symptoms for those with anxiety and depression diagnoses. These improvements were rapid, often apparent within the first three months, and generally maintained at the 12-month mark. Importantly, 70% of patients using opioids for pain were able to reduce or discontinue opioid use during the study, reflecting a possible role for cannabis in reducing dependency on more addictive medications (sciencedaily.com; medscape.com).
A deeper look into the study’s methodology demonstrates both its value and its limits: it was the largest of its kind and involved real-world patients across diverse backgrounds. However, like many cannabis studies, it did not include a control group (patients who did not receive cannabis), making it difficult to draw definite causal conclusions. Attrition was also an issue, with 38% of participants remaining after 12 months—a bias possible if those experiencing less benefit were more likely to drop out. Financial costs may have influenced this, as only higher-income patients could afford to remain in the program. Adverse events were not systematically recorded (medscape.com).
Still, Thai medical communities may find value in the results. In clinical practice, Thai pain specialists and sleep medicine experts are frequently asked about alternatives when conventional medications fail. As noted by a lead researcher from the University of Sydney, “Current clinical guidelines support prescribing [medical cannabis] to patients who are interested in trialling it for conditions not responding to conventional treatments, and our findings suggest any improvements would be apparent quickly and maintained long-term.” Yet, the same researchers also stress that more rigorous research is necessary to pinpoint optimal THC and CBD ratios for different health problems, and to understand which patients benefit most (PLOS ONE, 2025).
When it comes to sleep, insomnia is a leading reason for cannabis use globally and also in Thailand, where an estimated 30% of adults report sleep problems (pubmed.ncbi.nlm.nih.gov). Controlled studies show that some cannabis products—especially those containing both THC and CBD—can improve sleep scores in the short term for patients with chronic insomnia. A 2022 clinical trial found that a compound of melatonin and CBD was safe and effective for short-term relief; in other words, patients fell asleep faster and stayed asleep longer (pubmed.ncbi.nlm.nih.gov). But reviews caution that evidence for long-term efficacy is limited and adverse effects—including cognitive slowness and next-day drowsiness—are common, especially with inhaled or high-THC formulations (Wikipedia: Medical cannabis).
Pain relief remains at the heart of the “medical marijuana” movement. The QUEST study and others confirm that many chronic pain patients—including those with neuropathic or musculoskeletal pain—do report moderate, clinically meaningful improvements when using prescribed cannabis oils. For Thai patients living with severe pain for whom standard painkillers prove inadequate or dangerous, cannabis may offer an important adjunct. Moreover, the observed reduction in opioid use could offer public health advantages in preventing opioid dependence, a problem that, while not as widespread in Thailand as the US, is a growing concern in the region. However, the consensus among pain experts—including the Royal College of Anesthesiologists of Thailand—is that cannabis is not a “cure,” but may play a supportive role for some individuals when conventional therapies have failed (Johns Hopkins).
With benefits, however, come risks that demand honest attention. High dosages of cannabis—especially those rich in THC—have been well-documented to cause short-term side effects including dizziness, fatigue, hallucinations, and paranoia (Washington Post). More concerning are the emerging findings about possible long-term mental health effects. A 2025 genetic study led by Yale University researchers and published in Nature Mental Health found compelling evidence for bidirectional causality between cannabis use disorder and a range of psychiatric conditions: having anxiety, major depression, bipolar disorder, PTSD, or even schizophrenia increased the risk of developing cannabis use disorder—and vice versa (medicine.yale.edu). In other words, frequent cannabis users may be more likely over time to develop mental illnesses, challenging the popular belief that cannabis can treat PTSD or anxiety. In fact, the genetic evidence points in the opposite direction.
A senior psychiatry professor associated with the recent Yale study cautioned: “People might suggest cannabis use can be a useful treatment for, say, PTSD, but this analysis indicates otherwise. We show that over time, cannabis is more likely to cause PTSD than to treat it.” The authors urge clinicians to resist off-label prescribing for mental health conditions until randomized controlled trials clarify true benefits versus risks (medicine.yale.edu).
Reports of paranoia are not rare—and in rare but serious cases, cannabis use, particularly among young people, can trigger acute psychosis, hallucinations, or onset of schizophrenia in genetically vulnerable individuals (NYT). These risks are heightened by the presence of potent products in the unregulated market, something Thailand has seen since 2022’s rapid commercialization of cannabis. A Thai addiction counselor and member of the national mental health institute told the Bangkok Post, “We are increasingly seeing cases of young adults coming to emergency departments with panic attacks, paranoia, or even psychosis after trying high-THC cannabis—often from street vendors or homemade edibles.”
The challenge for Thailand is unique. Following the 2022 decriminalization, the country witnessed an explosion of cannabis products—ranging from therapeutic oils and balms to potent recreational edibles—often with little oversight regarding dosage or patient suitability (Wikipedia: Medical cannabis by country). While the Ministry of Public Health has continually updated safety guidelines, some provincial hospitals have reported rising numbers of cannabis-related ER visits, especially in urban centres like Bangkok and Chiang Mai.
Cultural attitudes toward cannabis in Thailand are complex. For centuries, cannabis (“ganja”) featured in traditional herbal remedies for pain relief and appetite stimulation, particularly in remote rural areas. This is reflected in ancient Thai medicine texts and oral knowledge passed down in villages. However, widespread use was criminalized by the 1979 Narcotic Act. Since liberalization, public attitudes are divided; some see cannabis as a natural “back to roots” remedy, while others fear it will undermine community health.
Given this shifting landscape, public health experts stress the need for robust patient education. A pain specialist at Siriraj Hospital observed, “Many Thais believe cannabis is completely safe because it’s natural, but most are unaware of critical issues like dosage, THC/CBD ratio, or drug interactions. There’s also an underappreciation of the mental health risks, particularly for teenagers and those with family histories of psychosis.” The risks of accidental ingestion by children and the lack of standardized product labeling further complicate the picture.
Looking ahead, what can Thais expect? If data from Australia and other countries is any indication, patients with chronic pain, sleep problems, and certain mental health conditions may find real but modest relief from prescription cannabis, particularly when conventional therapies are unaffordable or ineffective. Thai clinical trials are being planned, with government researchers emphasizing rigor in study design. Experts urge local authorities to prioritize public safety with proactive measures: robust product testing, clear patient education, tighter marketing restrictions (especially targeting youth), and more research on the precise impacts of cannabis on Thai populations.
For ordinary Thai readers, the new evidence points to several practical recommendations:
- Consult with a qualified healthcare professional before starting any cannabis-based therapy, especially if you have a history of mental health conditions or are taking other medications.
- Beware of high-THC products or unregulated street cannabis, as these are more likely to cause side effects and unpredictable experiences, including paranoia or panic attacks.
- If you notice new or worsening anxiety, depression, trouble thinking clearly, or signs of paranoia after starting cannabis, stop use and seek medical guidance immediately.
- Store all cannabis-containing products safely out of reach of children and pets.
- Watch for new announcements by the Ministry of Public Health regarding updated cannabis safety rules and approved medical uses.
Ultimately, while medicinal cannabis does offer hope for managing tough health conditions, the evidence is clear: benefits are modest, risks are substantial for certain groups, and careful, individualized supervision is critical. As with so many aspects of health, a cautious, informed approach will yield the best outcomes for Thai families navigating this new era of cannabis care.