Answer by taking a quote from the following article:

Born in New Orleans, Louisiana, Capote was the son of 17-year-old Lillie Mae Faulk and salesman Archulus Persons. His parents divorced when he was four, and he was sent to Monroeville, Alabama, where, for the following four to five years, he was raised by his mother's relatives. He formed a fast bond with his mother's distant relative, Nanny Rumbley Faulk, whom Truman called "Sook". "Her face is remarkable - not unlike Lincoln's, craggy like that, and tinted by sun and wind", is how Capote described Sook in "A Christmas Memory" (1956).

In the late 1970s, Capote was in and out of drug rehabilitation clinics, and news of his various breakdowns frequently reached the public. In 1978, talk show host Stanley Siegel did an on-air interview with Capote, who, in an extraordinarily intoxicated state, confessed that he had been awake for 48 hours and when questioned by Siegel, "What's going to happen unless you lick this problem of drugs and alcohol?", Capote responded: "The obvious answer is that eventually, I mean, I'll kill myself ... without meaning to." The live broadcast made national headlines. One year later, when he felt betrayed by Lee Radziwill in a feud with perpetual nemesis Gore Vidal, Capote arranged a return visit to Stanley Siegel's show, this time to deliver a bizarrely comic performance revealing an incident wherein Vidal was thrown out of the Kennedy White House due to intoxication. Capote also went into salacious details regarding the personal life of Lee Radziwill and her sister, Jacqueline Kennedy Onassis.  Andy Warhol, who had looked up to the writer as a mentor in his early days in New York and often partied with Capote at Studio 54, agreed to paint Capote's portrait as "a personal gift" in exchange for Capote's contributing short pieces to Warhol's Interview magazine every month for a year in the form of a column, Conversations with Capote. Initially the pieces were to consist of tape-recorded conversations, but soon Capote eschewed the tape recorder in favor of semi-fictionalized "conversational portraits". These pieces formed the basis for the bestselling Music for Chameleons (1980). Capote underwent a facelift, lost weight and experimented with hair transplants. Despite this, Capote was unable to overcome his reliance upon drugs and liquor and had grown bored with New York by the beginning of the 1980s.  After the revocation of his driver's license (the result of speeding near his Long Island residence) and a hallucinatory seizure in 1980 that required hospitalization, Capote became fairly reclusive. These hallucinations continued unabated and medical scans eventually revealed that his brain mass had perceptibly shrunk. On the rare occasions when he was lucid, he continued to promote Answered Prayers as being nearly complete and was reportedly planning a reprise of the Black and White Ball to be held either in Los Angeles or a more exotic locale in South America. On a few occasions, he was still able to write. In 1982, a new short story, "One Christmas," appeared in the December issue of Ladies' Home Journal; the following year it became, like its predecessors A Christmas Memory and The Thanksgiving Visitor, a holiday gift book. In 1983, "Remembering Tennessee," an essay in tribute to Tennessee Williams, who had died in February of that year, appeared in Playboy magazine.

What drugs was he on?
drugs and alcohol