I was paranoid from that moment on,” Oliver Stone tells biographer James Riordan. This should be good: What experience could possibly have prompted the onset of so fertile a paranoia?

Where in Riordan’s new book, Stone: the controversies, excesses, and exploits of a radical filmmaker (Hyperion, $ 24.95, 573 pages), does the answer lie? Could it be when Stone landed in the clink for marijuana smuggling on his 1968 return from Vietnam? (“He was a vet just returned from combat . . . who’d been thrown in jail and America didn’t seem to care.”) Or perhaps paranoia dates from 1975 and Stone’s unproduced but attention-getting script $ IThe Cover-Up, the first of his fictional works “to involve a government agency in a conspiracy” (it connected the dots between Uncle Sam and the Patty Hearst kidnapping)? Or maybe the pivotal event was as recent as 1990, when $ IBorn on the Fourth of July failed to bag a slew of Academy Awards in the aftermath of the first collision of Stone-made falsehood with verifiable fact? (“They’ll find something to make you look bad if they want to,” says Stone.) Reaching deep into the past, one ought not dismiss the miserable stretch in summer camp that Oliver Stone endured at age 4. Or does the answer lie elsewhere?