Dr. Alan Wofsey is a Clinical Associate Professor of Psychiatry at the University of Pennsylvania and former chief of Psychiatry at Lankenau Hospital.
"People who feel isolated, who've failed or been humiliated, often like to take out their anger on other people," he said.
Dr. Wofsey says many young men, like the suspect in Colorado, are having great difficulty finding their personal identities.
"It's very, very difficult for young men to live up to the goals and expectations that they have of themselves," he explained. "And many get angry and frustrated an opt out."
Dr. Wofsey also says that excessive marijuana use can bring out psychotic behavior in some young people.
"There is growing evidence that with the strength of marijuana use today, kids can become quite ill without realizing it's happening to them," he said.
Dr. Wofsey says for the young survivors of the movie theatre shooting there is a risk of post traumatic injury.
"There is the risk that young people will feel unsafe," he said, "maybe suffer nightmares, panic attacks."
Some, he says, may feel they're okay but find themselves unable to move forward.
"They may feel a sense of guilt," he said. "They may feel burdened by repetitive images."
And Dr. Wofsey said children on certain prescription medications, and adolescents who might be abusing their meds, are more vulnerable.
"Children or adolescents who happen to be taking stimulants like Adderall or Ritalin . . . that increases the amount of adrenalin in their bodies and makes them more susceptible to post-traumatic stress.
Dr. Wofsey says there are special techniques to treat post-traumatic stress. He said it's important for parents and family members to closely monitor loved ones who've experienced a tragedy like the theatre shooting, and to watch for signs of stress.