He said it was not only psychologists or trained personnel who could perform hypnosis or systematic persuasion, and added that con artists have regularly duped their victims successfully with well-planned methods and supported by other gang members.

Somchai said strong and effective persuasion could even lead to mass suicides among cult members, as has happened in other countries. He said hypnosis was once used for healing people with mental problems but it could also be practised for non-medical purposes by skilled hypnotists.

Dr Prakitpao is now under care at Galaya Rajanagarindra Institute after being moved from Srithanya Hospital following a Criminal Court order last week on the plea of a woman who claims to have been close to him for nine years. The institute doctors have not issued the latest report on his present mental condition.

Meanwhile, deputy director-general Dr Apichai Mongkol said a new bill to protect people with mental problems would soon be passed.

The bill grants legal immunity to police or state officials who order medical treatment for mentally-ill people without the consent of their families, if the mentally-ill people were abandoned or received no proper care.

Apichai also warned the public against excessive consumption of ephedrine, found in food supplements, and used widely by athletes.

The substance, extracted from ephetra herb, increases heartbeat and stimulates the nervous

system but is dangerous if overused.

Ephedrine is widely mixed with food supplements, and is known by the Chinese name Ma Hung. It is sold without licence in Thailand. The US Food and Drug Administration is studying whether to limit the use of ephedrine.