"The preliminary diagnosis he received is called brief reactive psychosis, an acute state brought on by the extreme exhaustion, stress and dehydration," the family said in a statement. "Though new to us, the doctors say this is a common experience given the great mental, emotional and physical shock his body has gone through in these last two weeks."
Russell, 33, was taken into custody by San Diego police Thursday after neighbors reported him running naked, pounding his fists on the sidewalk and shouting. He was taken to a mental health facility for observation, but wasn't arrested or charged, the Los Angeles Times reported.
Russell co-founded the non-profit Invisible Children, which has sought to publicize the atrocities it says have been committed by the African militant group Lord's Resistance Army, the Los Angeles Times reported.
The video has been viewed online more than 100 million times and the attention took a "serious toll on [Russell] and unfortunately, the whole world saw that," Ben Keesey, the video's producer said.
Notable deaths of 2014 [PHOTOS]