Addiction is likely the most relevant lens for understanding these jarring personality transformations. In Robert Louis Stevenson’s classic of doppelganger literature, The Strange Case of Dr. Jekyll and Mr. Hyde, Dr. Henry Jekyll turns back and forth into the murderous Edward Hyde when he drinks a mysterious serum; but over time, the serum stops working and the original Dr. Jekyll gets lost completely. When I look at the behavior over the past few years of several people I once knew and whose company and work I once enjoyed, it’s obvious that they are swilling a dopamine-releasing serum that has turned them, perhaps permanently, into digital-age versions of Mr. Hyde.

XREF: Connects the Jekyll-and-Hyde framework to the reader's interest in technology's psychological effects and behavioral addiction.

Naomi Klein, Doppelganger, loc. 344