A detailed view of a marijuana plant on Thailand's Koh Chang Island on June 9, 2022.Paul Lakatos/SOPA Images/LightRocket via Getty ImagesThailand's prime minister has called for a ban on recreational cannabis in a major U-turn.Srettha Thavisin said cannabis should only be allowed for medical purposes.Thailand was the first Asian country to decriminalize cannabis for recreational use in 2022.Thailand's prime minister wants to ban cannabis just two years after his country decriminalized it for recreational use.In a post on Wednesday, Prime Minister Srettha Thavisin called on the country's Ministry of Public Health to revise its list of illegal substances to once again include cannabis, and to publish new guidelines limiting its use for medical and health purposes only.Thavisin also urged Thailand's health and justice ministries to join forces to arrest those who escape drug treatment or fail to undergo treatment, in order to prosecute them.Drugs are a problem that destroys the future of the nation, he said, adding that government agencies need to work together to eradicate drug activity and show clear progress within 90 days.Thailand was the first Southeast Asian country to legalize medical cannabis in 2018, and the first Asian country to decriminalize recreational cannabis in 2022, according to Forbes.The country's former health minister, Anutin Charnvirakul, spearheaded the effort in 2022, announcing his ministry would give away one million cannabis plants to Thai households for license-free cultivation as soon as the drug was removed from the country's list of controlled substances, per The New York Times.However, since taking power last August, Thavisin has made clear his intention to overhaul the country's drug policy.His party ran on an anti-drug platform, pledging to eradicate drugs from Thai society, per Time magazine.In an interview with Bloomberg in September, Thavisin said Thailand needed to regulate cannabis because the country has a "widespread" drug problem.Other countries have legalized or decriminalized cannabis for recreational use in recent years, including Canada, Germany, Mexico, and South Africa.