A survey conducted between November 6 and 8 on 228 residents of the province's Muang and Pho Thong districts revealed that 35 per cent of them suffered mental health problems, permanent secretary for public health Dr Prat Boonyawongwirot said.

Twenty-five per cent were suffering from PTSD, he said, with symptoms including stress, nightmares, trouble sleeping and worrying about a recurrence of the disaster.

Doctors have prescribed them sleeping pills, he said.

Seven per cent are suffering from depression and have become suicidal. They have been prescribed anti-depressants and their relatives have been asked to keep a close watch on them, Prat said.

He said these patients had a history of accumulated stress and so could not cope with the prolonged flooding.

The ministry will continue monitoring the flood-hit residents for mental health problems - including suicidal thoughts, PTSD, depression and alcoholism - for the next three months, which is the period it would take most people to readjust their lives, he said.

About 10,000 booklets on relaxation methods will be distributed among the residents and a hotline (1323) will be kept open round the clock to advise on mental health problems, he added.

As for the main focus of the ministry's rehabilitation plan - to prevent epidemics such as leptospirosis, dengue fever, severe diarrhoea and hepatitis - Prat said officials had worked hard on tasks including sanitation, pest control and improving water quality.

He reported that the ministry had treated 670,453 people for waterborne diseases.