Dr Sirichai Silpa-archa, director of Patong Hospital, said that he first heard about the incident from the Narenthorn Emergency Center, which informed him that one boy and 21 girls had been affected.
At the hospital staff calmed them down, though some of the more serious cases, suffering from anxiety, seizures, muscle spasms or hyperventilation, were given Valium to calm them down.
Psychiatrists were also drafted in to talk to the children.
Health staff found that this was the second time in four days that this group had experienced mass hysteria. On Friday (June 28) they were on a visit to the Anti-Narcotics Training Project at Chulabhorn Marine Park Conservation Centre in Thap Lamu, Phang-Nga.
After their outbreak of screaming there, they had to be taken to hospital in Phang Nga but all appeared to recover quite quickly.
However, this morning, something once again sparked off the hysterics at a perfectly normal morning ceremony at the school.
Today, 13 of the students were released and told to go home, another six were also released but were told to call the hospital if they felt strange again, while three remain in hospital for observation.
Dr Sirichai characterised the incidents as “mass psychogenic illness”.