What can lead a teen to stab a 17-year-old he didn’t know 55 times, dancing and apparently celebrating as he did so? It could be a multiplicity of factors, including past trauma, intermittent explosive disorder and lack of impulse control, say mental health experts as details of the frenzied killing in Delhi this week unravel.

According to police, the 16-year-old accused attacked the victim in east Delhi’s Welcome colony on Tuesday after being refused money to buy biryani. Some of the chilling details of the killing were captured on CCTV, which showed the apparently inebriated teen slitting his victim’s throat, dragging him by the hair through the streets and gesturing to passersby to keep away.

According to forensic psychologist Deepti Puranik, the teenager’s behaviour could have been an onset of a psychological disorder that hasn’t been diagnosed yet.

Such an intense reaction to rejection - for the money he demanded -- can stem from suppressed emotions connected to a similar incident in the past, added consultant clinical psychologist Shweta Sharma.

Alcohol or substance use, academic struggles among a number of factors should be looked into to determine the reason behind the violent behaviour, said Pradipta Majumder, a child and adolescent psychiatrist practising in Pennsylvania in the US.

Noting that severe mental illness accounts for less than 5 per cent of homicides, Majumdar said, “Factors like prior violent behaviour, antisocial traits, childhood trauma such as sexual or physical abuse, parental influences, possession of weapons, and neighbourhood environment should be considered.” “Under-treated or untreated conditions such as conduct disorder, substance use disorder, bipolar disorder, or psychosis might contribute to violence,” Majumder told PTI.

In Puranik’s view, there are several elements to consider, including impulse control.

“He wasn’t able to control his impulse that is why he continued stabbing. Another possibility is of him having antisocial personality disorder or perhaps intermittent explosive disorder,” Puranik explained.

She added that in a person with intermittent explosive disorder, the “magnitude of aggressive outbursts is not premeditated and grossly out of proportion to the provocation”.

“There must have been some frustration from some past incident. Maybe he was getting such treatment from family members or his peer group. The situation of rejection, of not being allowed to do something could have triggered the behaviour,” Sharma, a panel psychologist at Juvenile Justice Board, Gurugram, told PTI.

In her view, the accused could be frustrated from some past incident and an associated personal issue.

“So it was just a kind of trigger that he got the opportunity to vent out all the frustrations, it was not directly linked to that person. He was a stranger. But this incident was the final nail in the coffin,” she noted.

To prepare for such incidents at a larger level, Sharma stressed on the need for creating a psychosocial environment for public awareness on mental health, especially related to adolescence issues.

“We need a proper psychosocial system in our society. We need to talk about body changes, we need to talk about psychological changes at a certain age… It could be about how to regulate your emotions, about sex education, about how to handle peer pressure. There should be some mohalla based community services to create awareness about mental health issues,” the psychologist said.

She also suggested that stress management sessions, emotion regulation sessions and empathic support counselling should be made a norm in society.

This is not the first killing in the open to shock the city this year.

In May, a 16-year-old girl was stabbed over 20 times and bludgeoned to death by a youth in northwest Delhi's Shahbad Dairy area. The two were in a "relationship" but had a quarrel a couple of days ago.

In another incident in October, a 27-year-old man stabbed a woman around 13 times on her face, thighs and fingers as he was not able to "cope" after her family rejected his marriage proposal for her and she blocked his phone number. The 23-year-old woman survived the assault.

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