Frances Wilson at The New Statesman:
De Quincey’s career as a journalist (he wrote one book in 30 years, and roughly 250 articles) coincided with the birth of a genre that Walter Bagehot called the “review-like essay and the essay-like review”. He was not an essayist in the polished manner of Hazlitt; he did not create finished objects. The virtue of the essay is that it reflects a thought in the process of discovering itself, and De Quincey dramatised this process. He wrote in diversions, he recycled other people’s words, he produced experiments in inwardness, works-in-progress; instead of moving his writing forward, he either plunged downward or rose, as Leslie Stephen said, “like the bat . . . on the wings of prose to the borders of the true poetical region”. Naturally, opium helped with the language of reverie. De Quincey was not an opium eater but a laudanum drinker: he took his opium as drops dissolved in alcohol, and a decanter of the crimson liquid was kept by the desk on which he wrote.
During breaks from his writing, he scuttled through the London streets in a state of high anxiety, confiding in John Taylor that he had a sort of ominous anticipation “that possibly there was some being in the world who was fated to do him at some time a great & unexpiable injury”: Taylor thought “Wilson might be the man”. Opium released De Quincey’s paranoia, but his fears were not entirely ungrounded. John Wilson was a dangerous beast, and De Quincey’s betrayal of Blackwood’s was bound to have repercussions. “These things Wilson can never forgive,” De Quincey said: “they will rankle in his mind: and at some time or other I am sure he will do what he can to injure me.”
more here.