A staff nurse lost his temper with an intellectually disabled patient who threw a food tray at his colleague, kicking the patient at least four times.

Yesterday, S. Ahmad Shazaly S. Affindy (photo), 27, was sentenced to six months' jail after pleading guilty to causing hurt to the 56-year-old man, who is unable to speak.

The court heard that on May 17 last year, the patient at the Institute of Mental Health (IMH) had thrown his tray at a nurse after eating his lunch.

She picked it up and told Ahmad Shazaly, who was on duty, about it. Ahmad Shazaly confronted the patient and decided to take the man back to his room so he could be restrained. When they reached the room, the older man laid on the floor instead and refused to move.

Enraged, Ahmad Shazaly kicked the patient's back at least four times. He grabbed the man by the collar and dragged him along the floor for about 2m before the man eventually got up.

About six hours later, another nurse noticed the patient's right hand was swollen with some discolouration. An X-ray done the next day revealed a fracture on his right little finger.

When staff members checked closed-circuit television footage, it showed Ahmad Shazaly assaulting the patient. IMH reported the matter to police.

Deputy Public Prosecutor Zhuo Wenzhao, in urging District Judge Jasvender Kaur to sentence Ahmad Shazaly to at least eight months' jail, said: "The accused had abused his powers by assaulting the victim and then tying him to the bed with restraints."

Mr Irving Choh, who represented the accused, appealed for a shorter five-month sentence.

"It is a known fact that a large number of nurses and healthcare professionals suffer from caregiver syndrome, (which) causes anxiety and stress," he said.

Ahmad Shazaly, who is out on bail of $10,000, was ordered to surrender himself at the State Courts on July 5 to begin his sentence.

Responding to queries from The Straits Times, IMH said his employment was terminated last July.

A spokesman said existing safeguards were further reinforced and its workers were reminded of protocols.