When Rehnquist, then an associate justice, was hospitalized and taken off Placidyl, he suffered such severe withdrawal symptoms that he became delusional and thought the CIA was plotting against him, the Washington Post reported. Doctors then put him back on the drug and weaned him off it successfully by early 1982.
The FBI released the more than 1,500 pages of documents to a number of journalists and scholars under a Freedom of Information Act request. The documenets could not be released before Rehnquist's death in 2005.
The files show that the FBI investigated possible Democratic witnesses at Rehnquist's confirmation hearings in 1971 and 1986. In 1971, President Richard Nixon was concerned because his two previous nominees had failed to win confirmation.
Alexander Charns -- a Durham, N.C., lawyer and one of the people requesting the files -- said they show "the ongoing use of the FBI for political purposes, not only in the '60s and '70s but well into the 1980s."
An FBI spokesman denied any partisan tilt, saying all witnesses are investigated.
Celebrity Breakups and divorces of 2014 [PHOTOS]