“There is nothing more powerful than the made-up mind.”

Romancing Opiates: Pharmacological Lies and the Addiction Bureaucracy (2006)

Bk. 1, Ch. "Paradox, Next Stop After the Boondocks
The Shockwave Rider (1975)

Source: Tropic of Cancer

Last words, to his niece, according to A Colored Man's Reminiscences of James Madison (1865) by Paul Jennings, p. 20; his testimony on his death reads:
:: I was present when he died. That morning Sukey brought him his breakfast, as usual. He could not swallow. His niece, Mrs. Willis, said, "What is the matter, Uncle Jeames?" "Nothing more than a change of mind, my dear." His head instantly dropped, and he ceased breathing as quietly as the snuff of a candle goes out.
Variant:
I always talk better lying down.
Last words, according to a listing of "Last Words of Famous Americans" in A Conspectus of American Biography (1906) edited by George Derby, p. 276; no prior publication of such an attribution has been located; in recent years, without any sources cited, the two divergent accounts of his last words have sometimes been combined into the form: "Nothing more than a change of mind, my dear. I always talk better lying down."
1830s

Patheos, Philosophistry http://www.patheos.com/blogs/reasonadvocates/2017/04/12/philosophistry/ (April 12, 2017)

Source: The Victorian Age in Literature (1913), Ch. II: The Great Victorian Novelists (p. 73)

Source: The Burning Secret and other stories

Letter to Simón Bolívar (27 September 1829). Quoted in The Life of Major-General William Henry Harrison: Comprising a Brief Account of His Important Civil and Military Services (Philadelphia, PA: Grigg & Elliot, 1840)