Elizabeth Vargas Checks Back Into Rehab

"20/20" co-anchor Elizabeth Vargas has checked into rehab for alcohol abuse ... the second time she's done that in less than a year.

Vargas says, "As so many other recovering alcoholics know, overcoming the disease can be a long and incredibly difficult process. I feel I have let myself, my co-workers and most importantly my family down and for that I am ashamed and sorry."

Vargas spent a few weeks in rehab late last year for alcohol abuse.