Psychiatrists said a high-profile road rage incident on Wednesday in which a young overseas-educated Thai criticised fellow Thais, earning the displeasure of a large crowd who gathered outside the police station where he was charged, was unlikely to have been a symptom of depression as the perpetrator declared.

But they added that while the driver's mental health claim remains to be proved, those offended by his tirade against the nation and the monarchy should refrain from retaliating or violating his rights.

The media and public critics should stop delving into the driver's personal life and instead give him some sympathy, said Yongyud Wongpiromsarn, an adviser to the Mental Health Department.

Any person, regardless of whether they suffer a mental illness, can lose their temper, which underlines the importance of anger management as a life skill, said the doctor.

"A mental problem should never be cited to explain why someone behaved badly to others, as doing so can lead to more discrimination against mental patients," said Kiattibhoom Vongrachit, director-general of the department.

A probe by mental health experts will be required to find out if the driver is suffering from a mental disorder as claimed and also whether his illness really was to blame for the road rage, said a fellow psychiatrist in the department.

"However, mental illness cannot always be cited as a reason to acquit someone of wrongdoing," he said.

Rachata Wangitcharoensuk, 24, made headlines after Nanthawat Kamolrum posted photos and two video clips on his "To Jetdo" Facebook page of the incident on Wednesday.

Mr Rachata lost his temper after his car hit a pickup driven by Mr Nanthawat, 22.

Mr Rachata made negative remarks about the monarchy at least twice in the clips.

Both went viral, with 18 million and almost 6 million views by Thursday afternoon, along with an outpouring of criticism on social media.