Cannabis-related treatment costs rose from 3 billion to 20 billion baht last year due to a surge in usage among the population, says the Public Health Ministry.
During a public hearing on Saturday on cannabis use and its effects on society, Minister Somsak Thepsutin said that since its decriminalisation, more people have been getting sick and suffering from mental illness. He added the government sets an annual budget for treating people under the universal health care programme.
"The budget for the treatment of patients who used cannabis jumped from about 3 billion baht since cannabis was delisted from a narcotic drug to 20 billion baht last year. This is very high and makes us worried about cannabis use," he said.
In addition, research in the US found the IQ of children dropped eight to nine points after they used cannabis, as the plant affects brain development in children. The findings concern the government, he said.
He said the hearing on Saturday, which brought together youth, doctors and medical bodies, and civil society networks, was part of the government's attempt to relist cannabis, especially cannabis buds, as a narcotic by the end of this year.
The current regulation only lists cannabis extracts with more than 0.2% tetrahydrocannabinol (THC) of total weight as a narcotic.
Kriangkrai Puengchuea, from the Substance Abuse Academic Foundation, said 7,700 cannabis shops had opened nationwide since the plant was legalised.
Those shops sell dry cannabis buds and cannabis-related products, allowing customers to use cannabis recreationally. A survey conducted in a Western country showed that 40% of heroin users started their drug journey using cannabis.
Dr Manit Sisurapanont, president of the Royal College of Psychiatrists of Thailand, said research in the US found people get addicted to the use of cannabis, which leads to mental health problems. In the long run, the use of cannabis can lead to IQ reduction and mental disorders.
Dr Prakarn Thomyangkoon, a member of the Psychiatric Association of Thailand, said using cannabis might lead to suicide attempts by heavy users, and the substance from the plant can contaminate breast milk.
Arthit Satienwaree, from the Youth Network Against Cannabis (YNAC), said public awareness of cannabis usage was low, as some think the plant can be used anywhere since it is legal.
The misunderstanding led to community-grown cannabis as well as misuse of the plant, including incidents of it being mixed with snacks, which were then eaten by children without their knowing, he said.
YNAC supports the government's relisting of the plant as a narcotic due to widespread concerns over the impact of cannabis use on the health of teenagers and kids.