TEANECK — The former Ivy League student who vanished in December lost touch with reality after an addiction to energy supplements and penis enlargement pills, Timothy Hamlett's family tells The Daily Beast.

The family believes supplements like Pygeum, Ginseng Panax, Vitalikor Male Enhancement, Big Jim and the Twins Penis Enlargement were responsible for the 20-year-old developing psychosis shortly before his disappearance.

Hamlett, a former track star at the University of Pennsylvania, hopped a jitney near his Teaneck home into Washington Heights in Manhattan on Dec. 26. It's the last time he's been seen or heard from.

"Our son did not experience any issues until he started taking these supplements," mother Katherine Hamlett told the publication, noting the addiction began in Sept. 2013. "And people look at us cross-eyed and I know there's a lot of skepticism. But if you look at the history he goes all the way through school--no issues whatsoever and then he starts taking these supplements and everything in his life, literally everything in his life changes."

The Hamletts removed their son from school after he began showing signs of what they thought could be schizophrenia, they told The Daily Beast. Experts told the site that it was inconclusive if the stimulants Hamlett had taken could have caused psychosis.

Timothy was arrested in connection with a brick-heaving spree that resulted in property damage to vehicles, houses and one injury. His attorney says he doesn't believe the arrest is related to his client's disappearance.

James Kleimann may be reached at jkleimann@njadvancemedia.com. Follow him on Twitter @jameskleimann. Find NJ.com on Facebook.