. >> reporter: in fact, medical experts see clear evidence of mental trama among residents in neighborhoods of cities such as oakland. posttraumatic stress disorder or ptsd. >> it's absolutely true. >> reporter: mark serves as director. >> not the same as a soldier. a soldier goes to war and they come home. marks is especially trained psychological counselor that deals with the results of the violence while trying to break the psychole. >> we work with young people that get shot, go to the hospital. get their treatment, come back to the same community. maybe the same home where they were shot in front of. >> reporter: youth alive visits every family victimized by gun violence in oakland. their crisis response team is often at the home of the family before police are finished investigating. >> there is no post to the traumatic stress. it's continuing traumatic stress disorder and that the unique. >> posttraumatic stress is very real. >> reporter: ask lorraine taylor. >> when i read the scripture. >> reporter: taylor lost both her twin boys in shootings in oakland. >> i sat on my bed the othe