[I]n 1986, the FBI conducted an intensive investigation into Rehnquist's dependence on Placidyl, a strong painkiller that he had taken since the early 1970s for insomnia and back pain....
The FBI's 1986 report on Rehnquist's drug dependence was not released at the time of his confirmation [as Chief Justice], though some Democratic senators wanted it made public. But it is in Rehnquist's now-public file, and it contains new details about his behavior during his weeklong hospital stay in December 1981. One physician whose name is blocked out told the FBI that Rehnquist expressed "bizarre ideas and outrageous thoughts. He imagined, for example, that there was a CIA plot against him."
The doctor said Rehnquist "had also gone to the lobby in his pajamas in order to try to escape." The doctor said Rehnquist's delirium was consistent with him suddenly stopping his apparent daily dose of 1400 milligrams of the drug -- nearly three times higher than the 500-milligram maximum recommended by physicians. The doctor said, "Any physician who prescribed it was practicing very bad medicine, bordering on malpractice."
January 3, 2007
"Rehnquist expressed 'bizarre ideas and outrageous thoughts. He imagined, for example, that there was a CIA plot against him.'"
From the newly released FBI file on William H. Rehnquist: