Georgia knew something was up with Alex. She liked to spar with Henry in group, but today her friend had let him grind on, ignoring obvious chances to swat his ego.

‘Our au pair drove all the bloody way from Hertfordshire with my Xbox,’ Henry ranted, growing more irate with every sentence. ‘I set up a death match with my buddies in the rec room. Then Keith the nurse strides in. Sees my HDMI lead going from the Xbox to the telly on the wall and tells us it’s too long.

‘I know we’re not allowed to have long cables so us loons can’t neck ourselves. But he wanted to take it right there, with the three of us mid-tournament. I said I’d hand the cable in at the nurses’ station when we’d finished playing and get our au pair to bring a shorter cable …’

Tanvi the therapist made a stop-talking gesture. Then spoke with a lisp that made sss come out like thh.

‘This is where you lost your temper and there was an incident?’

‘I hardly lotht my temper,’ Henry mocked, sitting up defensively and tucking his feet under the chair. ‘Keith tried to yank my Xbox cable. I pushed him away and he tripped on the stack of board games. Keith charged back to the nurses’ station and made a tiny incident into this huge thing. The night manager came out, saying she was locking the rec room, and made us all go back to our rooms …’

‘Let’s pause there,’ Tanvi interrupted. ‘Henry has issues with impulse control and this is a good opportunity to discuss techniques that could have stopped a situation from escalating.’

Georgia cringed at Tanvi calling Henry’s problem impulse control. ‘Nasty thug’ felt more truthful.

Henry’s story was known around the unit. He’d been dumped by his boarding-school girlfriend. A couple of months later, he’d seen her kissing a music student at a house party. Henry sucker-punched the student, shoved him down a flight of stairs and stomped his head into a four-day coma.

Any ordinary brat would have bounced to jail, but Henry’s daddy found a fancy lawyer, who paid an even fancier psychiatrist to write a report, claiming that Henry had cognitive issues and had been suffering from depression, which led to his outburst of ‘uncharacteristic behaviour’.

So Henry got to spend nine months at the Freeman Unit, bleating about his Xbox getting confiscated, instead of three years in young offenders with lads whose parents didn’t own three houses and a sixteen-metre racing yacht.

‘What behavioural technique could Henry have used to help control his anger?’ Tanvi asked the five patients.

Ross broke a moment’s silence. ‘That thought, feeling, behaviour, triangle thingy?’ he guessed, keen to please.

Tanvi shook her head. ‘The cognitive triangle is used to understand how our feelings affect our behaviour. I’m talking about a specific technique that I mentioned earlier in this session …’