Young men who are street gang members are prone to suffering from high levels of psychiatric illness, according to a study conducted by researchers from Queen Mary, University of London.

The first-of-its-kind study established a possible link between gang violence and psychiatric effects.

"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," said, Professor Jeremy Coid, Director of the Forensic Psychiatry Research Unit at Queen Mary, and lead author of the paper.

The study found out that the percentage of young men in gangs was higher in small boroughs when compared to the percentage of gangs in cities.

For the study, the researchers approached 4,664 British men, aged between 18 and 34, from areas with high gang membership, lower social classes and from places with a higher than average population of ethnic minority residents.

These men were asked questions related to gang membership, violence, use of mental health services, and psychiatric diagnosis.

Around 70.4 percent of the participants said that they had not involved in any act of violence for the past five years; 27.3 percent of them reported to be in a fight or assaulted someone, while 2.1 percent of them admitted to being a current gang member.

The researchers then classified these men into three groups: gang member, violent, and non-violent and analyzed them. The results revealed that violent men and gang members tend to be younger and unemployed than the non-violent men.

They were also likely to have a psychiatric illness and use mental health services than non-violent men.

Violent ruminative thinking, violent victimization and fear of further victimization were observed more in gang members. Authors also noted high level of suicidal tendencies among gang members which was due to their psychiatric illness.

However, depression was observed less among violent men and gang members than non-violent men.

"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. However this could only partly explain the high prevalence of psychosis, which warrants further investigation," Coid said.

"With street gangs becoming increasingly evident in UK cities, membership should be routinely assessed in young men presenting to healthcare services with psychiatric illness in urban areas with high levels of gang activity."

The research is published today in the American Journal of Psychiatry.