"It's their understanding that when Xanax is taken in large amounts, or more than the prescribed dosage, these are some of the side effects. Xanax isn't being blamed for causing Elliot to go on his rampage, but it probably wasn't the best decision to have someone like him on it."

As law enforcement begins to piece together the days leading up to UCSB mass shooter Elliot Rodger's bloody rampage, disturbing details about the community college student's dependence on Xanax, which according to sources, made the son of Hunger Games' second unit director, Peter Rodger, more withdrawn, lonely, and anxious, RadarOnline.com is exclusively reporting.

Based on interviews with Elliot's parents, Peter and Li Chen, the Santa Barbara Sheriff's Department "is being told that he was likely addicted to Xanax . . . Peter and Li have been doing basic research on addiction to Xanax, and based on what they have read, they believe the tranquilizer made him more withdrawn, lonely, isolated, and anxious," a source told Radar.