Hundreds of others still receive some form of psychiatric treatment, they said.

Children show fear when they hear news about earthquakes or tsunamis and when seeing large waves, Dr Benjaphorn Panyayong, a director of a rehabilitation centre for victims, said. Most still have nightmares and many refuse to return to homes in areas hit by the Boxing Day disaster, she said.

More than 5,000 children in the six southern provinces affected were diagnosed with stress disorders in the immediate aftermath of the tsunami, she said.

In Phang Nga, around 8 per cent of 300 children being monitored were still believed to be suffering from serious mental illnesses, while 42 per cent still showed symptoms of stress disorder, she said.

Parents of children whose bodies were never recovered show symptoms, she said, adding some admitted contemplating suicide.

Dr Kobchoke Joowong, director of Suan Saranrom mental hospital in Surat Thani, said the total number of Phang Nga patients given psychiatric therapy was around 2,000. Therapists continued to make house visits, with help from psychiatrists in cases where medication was prescribed.

Those in need of intensive care are admitted to hospitals or a new psychiatric centre in Khao Lak.

As many as 40 patients have been hospitalised for aggression and insomnia.

Dr Weera Choorujiphorn of the centre in Khao Lak said the need for the clinic would be re-evaluated next year.

He expected a full recovery in all patients by that time.