In medical shows, sometimes a situation arises where doctors contemplate putting a patient into a coma on purpose for health reasons. The usual explanation is that doing so would somehow make it easier for the brain to heal itself.
I’m assuming that these doctors are using a more sophisticated method than simply a blow to the head, so how do they put someone in a coma? And what kind of injury would be lessened while in a coma versus simply letting him rest while awake?
Such comas are induced and maintained with medications. My understanding is that the coma per se does not aid in healing. But it is used to lessen / eliminate the discomfort for a patient who has to endure therapeutic measures that are very irritating to a conscious person - a chief one being prolonged intubation (breathing tube placement) with concomitant mechanical ventilation.
Several years ago, my nephew had surgery on tendons/ligaments in both legs. His doctors wanted him to not move his legs for 24-36 hours after surgery. So they gave him heavy doses of morphine – he was pretty close to a coma from that – he just slept for most of that time.
A medically induced coma is used in certain types of head injuries. The effect is to reduce swelling and pressure (somehow - I am not a doctor, so I’m not at all clear on how that works) that both reduces further damage and facilitates recovery over the long term. It also reduces the chances the patient will experience seizures, which can also be bad for long term recovery. Said coma is induced by drugs, not violence.
A medically induced coma isn’t much like the movie/TV comas. The patient is intubated (breathing tube) and placed on a ventilator. One or more central IV lines and an arterial line are placed to both adminster the needed medications and monitor vital signs. In the case of severe head injury, an ICP monitor (ventriculostomy) is also placed to monitor the pressure inside the skull. The patient is given a combination of drugs to sedate and paralyze. The sedatives used also slow brain activity. Barbituates are often the drugs of choice for sedation. There are a number of paralytic drugs, both short and long acting used to keep the person still. These drugs also paralyze the respiratory muscles, so the ventilator does all the breathing.
Maintaining a coma is fairly labor intensive for the nurses. The person must be turned frequently to keep fluid from building in the lungs, eyes must be lubricated about once an hour to avoid damage. Muscles have to be exercised. And the medications have to be carefully monitored and titrated. Secretions build up in the lungs that have to be manually suctioned out periodicly. Suctioning, as well as many other procedures can cause the ICP (intercranial pressure) to spike, care must be taken.
At one time insulin therapy was used to treat psychotic patients. It involved giving them enough insulin to induce the coma, but not quite enough to kill them (sometimes they got it wrong). Also made them photophobic, so the ward had to be darkened and the staff had to work with flashlights.
They used barbituates for the same treatment 10 years ago, I don’t know if they still do, it was falling out of favor then.
Doctors kept my father in a medically induced coma for about 4 months after his massive brain hemorrhage. This is common procedure whenever the brain is damaged and swollen - his was so swollen that they removed a large piece of his skull to give it more room (he had a big hole in his skull covered only by skin for nearly two years). Later, he developed a systemic infection which had him on the brink of death for quite a while. Once he recovered from that, they let him regain consciousness.
I don’t really know why it’s helpful to put people in comas after brain injuries, but it happens quite a bit.
If anyone is wondering he had a miraculous recovery (compared to his prognosis) even though he lost a good third of his brain. 
Just a note to say that the first time I scanned the list of topics I read commas for comas and assumed it was a punctuation problem!