A look into the mental health of gang members can help doctors identify underlying issues in at-risk youth.

Humans have always lived and hunted in packs, and it’s helped us evolve into what we are today, but new research into modern-day gangs reveals the true nature of the kill-or-be-killed lifestyle.

Researchers from Queen Mary, University of London, say young men who affiliate with gangs have unprecedented levels of psychiatric illness, especially antisocial personality disorders, anxiety disorders, and drug and alcohol dependence.

Jeremy Coid, lead study author and director of the Forensic Psychiatry Research Unit at Queen Mary, said the findings could be used to to help identify at-risk young men in areas of high gang activity in order to intervene with the appropriate mental healthcare.

Researchers surveyed 4,664 men ages 18 to 34 in Britain living in areas with high gang membership, a depressed economy, and a high percentage of ethnic minorities. Two percent of the men identified themselves as members of a gang. The men fit the stereotypical mold for a gang member: younger than their nonviolent peers and more likely to be unemployed.

When it came to their mental health, gang members—and men who said they’d recently been in a fight—were significantly more likely to have some form of mental illness.

“No research has previously investigated whether gang violence is related to psychiatric illness, other than substance misuse, or if it places a burden on mental health services,” Coid said in a press release. “Here we have shown unprecedented levels among this group, identifying a complex public health problem at the intersection of violence, substance misuse, and mental health problems among young men.”

More than half of the gang members suffered from anxiety and a quarter screened positive for psychosis, which researchers say could be explained by their propensity for violence, ruminating on violence, and likelihood of being violent-crime victims themselves.

“It is probable that, among gang members, high levels of anxiety disorder and psychosis were explained by post-traumatic stress disorder (PTSD), the most frequent psychiatric outcome of exposure to violence,” Coid said. “However, this could only partly explain the high prevalence of psychosis, which warrants further investigation.”

It should come as no surprise that nearly 86 percent of the 108 gang members surveyed fit the bill for antisocial personality disorder, which by definition sums up the thug life: disregarding the law, violating the rights of others, and manipulating and exploiting others. However, more than a third—34.2 percent—also admitted to previously attempting suicide.

Researchers said the suicide attempts may be explained by other mental illness, but may also be in line with the notion that “impulsive violence may be directed both outwardly and inwardly.”

The exception to their mental health woes, however, was depression. Gang members and violent men were significantly less likely to suffer from depression, researchers at Queen Mary, a public research university, said in their study published in the The American Journal of Psychiatry.