"Oh, just, subtle, and mighty opium!" exclaimed the 19th-century essayist Thomas De Quincey in his classic addiction memoir Confessions Of An English Opium-Eater. "What an upheaving from its lowest depths, of the inner spirit!" he enthused on its effect, adding: "Here was the secret of happiness, about which philosophers had disputed for many ages."
De Quincey had a childhood that was traumatised by the death of his sister, followed by his father dying a year later. Throughout his life, he was afflicted with depression and attacks of facial pain (a condition now known as trigeminal neuralgia) which drove him to an apothecary where he bought some opium. Not only did the pain disappear after he took it, he was transported to what he called an "abyss of divine enjoyment".