I worked in two different residential treatment facilities for children. These are places that used to be orphanages, but nowadays have switched to treatment facilities. The truth is that children without issues don't stay in residential more than a few days and then they are placed into foster care. (I'm in the USA, by the way.)
95% of the children I worked with were violent, at least at times. 100% of the children I worked with suffered abuse at some point in their lives. These are children who move from facility to psych ward to facility to foster care with their belongings packed in a garbage bag. They take their few possessions everywhere they go, or they lose them.
A good day was when we could keep everyone calm and didn't have to use Safe Crisis Management (Physically holding children so they cannot harm themselves or others.) A good day rarely meant we were able to teach the residents things that would help them. Some days, if we could get them to all sit down and eat without fighting then we were awesome. The units are overcrowded and under staffed. Resident injuries were rare, and caused by things like playing ball or falling off a bike. Staff injury was common and ranged from scratches and bites to broken ribs. I can't tell you how many times a child threatened me with a chair held over their head, but I was luckily never hit with one.
Children most often became violent when something caused a flashback to bad times, or when they were frightened. These kids suffer from PTSD, and the fight instinct was more common than the flight, though we had that too.
Training for staff was incomplete at both places I worked. Physical holds are taught extensively, as mandated by the state. Most staff I worked with had little understanding of the psychological side of resident's treatment, and could accidently escalate violent behavior rather than deescalate.
There aren't enough beds. Because of this, and because of inbounds honest desire to take in and help as many children as possible, children were put into units they had no business being in. 13 year olds that became violent with young children were housed in the same unit as five year olds. The few non-violent children waiting for foster care placement were thrown in with violent children. One such child related to me how terrifying it was to watch 3 adults hold a violent child on the floor on her first night in placement. Children, who have few to no issues when they arrive, end up with issues if they stay in placement very long.
Residents see a counselor once a week for 30 minutes, if they are lucky. They see a psychiatrist once every month or two. These visits rarely last more than five minutes. The psychiatrist asks if they are having any trouble with their meds, and then says b-bye. Understandably, with so little actual psychological help, these children have little chance of improvement. Most mental care is left to those staff that work with the kiddos on a daily basis, barely trained staff such as I was.
I knew a 10 year old girl who had already had over 50 placements. I knew a girl who was driven to the homeless shelter and dropped off on her 18th birthday. I knew a 14 year girl who ran away from the home, showed her boobs to passing motorists to get a ride, and was picked up by an older man. I also knew the awesome, underpaid and overworked staff member who ran down that car on foot and shouted at the driver until he kicked the girl out of his car. I worked with a large tween boy who was a psychopath, and did things like throw bricks from the landscaping at other residents to "see what would happen." He was housed with residents as young as five. I had a full out argument on the phone with incoming about how they could not house a teen boy who had been convicted of raping younger children with the pre-teen sexually active girls I had on my unit. I won that one. I worked with so many teen girls who were basically thrown away by their family. It made me wonder at how broken our society is that we throw away our teen girls. Every city could build two more residential places for teen girls, and there still wouldn't be enough beds.
This was all in residential placement. A client had to do something pretty horrible to be sent to a psychiatric hospital.
I want to be clear about one thing, few daily staff were there just to pick up a paycheck. Let's face it, at 10 bucks an hour, there are safer jobs. Most staff had suffered some sort of abuse as kiddos themselves, and were there to try to help. Our kiddos were broken and violent, and we loved them like they were our own kids. It is difficult and heartbreaking work, in a place where the system doesn't seem to care much about helping the kids. Many staff don't make it past a few years. Most new staff don't make it past a few weeks. I miss my kiddos, but the job got too dangerous for me, and it made me too sad.
As broken as the system seems, as scarce as beds are, children at least have mental care facilities to go to. Adults often end up on the street.
I am happy to answer any more questions you have. I will not disclose exactly where I worked, or anything overly specific about the kiddos in respect to their privacy.