What may have triggered the Hollywood gunman's rampage? Clinical psychologist explains

Over the weekend, more details began to emerge about Tyler Brehm, the gunman who opened random fire on drivers in Hollywood on Friday morning and was subsequently killed by police after injuring two men.

Brehm recently underwent a bad breakup and was given pills from a woman who "he thought" was a pharmaceutical salesman, according to his ex-girlfriend, who spoke with CNN affiliate KTLA.

Clinical psychologist Dr. Jeffrey Gardere joins American Morning today to weigh in on how these factors may have influenced Brahm's rampage.