Cannabis has been known as a herbal plant with psychoactive effects for thousands of years. The herb has been used for both medical and recreational purposes. As the plant is addictive, several countries have categorised it as a narcotic drug.
Thailand banned marijuana 90 years ago in 1934. Some Thai people also saw the impact of the recreational use of the drug by US soldiers during the Vietnam War in the 1970s.
Since, however, cannabis addiction is relatively mild compared with other narcotics, dozens of countries started to ease the ban more than a decade ago, allowing for medical cannabis or medical marijuana, while several countries granted a certain level of recreational use as well.
In Thailand, the former Prayut Chan-o-cha government (Prayut I) permitted the use and research of medical cannabis in February 2019. In late 2020, the Prayut II government eased the ban further, maintaining control only on flowers, seeds, and extracts with THC exceeding 0.2%. By June 9, 2022, it removed the herb from the narcotic drug list before putting its flowers on the herbal control list about six months later. After delisting, it was found that the number of users -- including those wanting to give it a try -- for recreation use significantly increased compared to the medical cannabis group.
Clinical-trial research studies in several countries suggest that while cannabis extracts, as well as some synthetic cannabinoids, have medicinal benefits for treating some illnesses or symptoms, particularly nauseating in cancer patients as a result of chemotherapy, a boost of life quality for patients in the terminal stage of palliative care, and two types of intractable epilepsy in paediatrics; there are other medicines that give similar results, but most with lesser risk and side effects. Some medicinal drugs, including synthetic opioids such as methadone, are also cheaper than cannabis.
Together, they are probably the reasons why none of the Royal Medicine Colleges -- that design the training programmes for specialists in each branch of medicines in Thailand -- recommend cannabis as a main medicine or the first-line drug for treating patients with any diseases or symptoms.
The minister of public health and some top public health officials in former administrations strongly pushed for medical cannabis in such a way that the Ministry of Public Health (MOPH) has added several key performance indicators (KPI) that seem designed to pressure its physicians to actively prescribe more cannabis to general patients.
However, most physicians at the ministry-run hospitals tended to follow the Department of Medical Services' official "Guidelines on Medical Cannabis" (now in their 2022 or 5th edition) which recommends prescribing medicinal cannabis for a handful of diseases or symptoms, but only if the patients do not respond to standard treatments.
According to the Health Data Centre (HDC) at the ministry, nine out of 10 patients prescribed cannabis products at MOPH hospitals from October 2020-March 2024 were seeking treatment from traditional medicine, where doctors prescribed cannabis mainly to treat insomnia or severe pain and migraines. Modern-medicine doctors also prescribed cannabis to treat insomnia; chemotherapy-induced nausea and vomiting, pain, and stimulate appetite in cancer or Aids patients and those suffering from two types of paediatric intractable epilepsy that are resistant to standard treatments.
To date, there is still a lack of sufficient research to support or recommend using cannabis to treat patients with Alzheimer's, Parkinson's, other types of epilepsy, acute pain, diabetes, hypertension, glaucoma, and schizophrenia.
As for insomnia per se, we have not found any modern-medicine institutes that recommend using cannabis as a standard treatment besides those in palliative care, partly because of concerns over long-term effects like drug tolerance that results in the need to increase the amount to be taken and the risk of drug dependence/addiction in the longer term. Even though some herbal practitioners argue that cannabis works wonders for insomnia, ruling out concerns for addiction, there are not enough scientific research and long-term clinical trials to support the claims, whereas there are reports that some users of cannabis oil for insomnia have to increase the doses repeatedly to 10-fold to have the same effect, and some cannot fall asleep without taking it.
Besides, there are health risks from consuming raw cannabis, given that the herb -- when compared to other plants -- can absorb pesticides as well as heavy metals from the soil relatively well. The latter risk remains to be found in organic cannabis. Consuming contaminated cannabis can be a health hazard that makes cannabis that had been promoted as a herb a major health concern in the long run, especially if the people take part in the cannabis promotion campaign launched by the former government with little or no knowledge of such effects.
Policy recommendations
It is necessary that the government attaches importance to the impact on the public's health when implementing cannabis policies and putting in place cannabis-related health indicators rather than using certain indicators to selectively promote certain substances or drugs.
Moreover, the government should develop a follow-up system to evaluate the impact of cannabis policy changes, covering both medical and recreational cannabis, and support sufficient clinical trials for medicinal cannabis to prove its effectiveness and safety in comparison with modern medicine before recommending it against any existing standard treatments.
In addition, the government should make use of infrastructure invested in cannabis research and development, not only for cannabis but also for other potential medicinal herbs, including those with addictive effects. This will help establish knowledge about the medicinal benefits and safety of both cannabis and other plants.
The government should also put an end to measures that could be harmful to people's health, like promoting household-level cannabis planting. It should curb advertisements of cannabis and other herbs as well as plants with addictive components, as long as there are no concrete research works to support the medicinal benefits. It must also place strict control on all adverts, ensuring there are no exaggerated claims.
Viroj NaRanong, PhD, is Research Director, Health Economics and Agriculture; Wuttipong Tunyut is researcher, at Thailand Research and Development Institute. This article is part of a 'Research plan on health, economic and social impacts from cannabis and related products' supported by the National Research Council of Thailand (NRCT) and the committee on research guidelines for national crisis management with regards to cannabis, Thailand Science Research and Innovation (TSRI). Policy analyses from the TDRI appear in the 'Bangkok Post' on alternate Wednesdays.
