It's plausible and popular to conclude that unnecessary testing and treatment comes largely from "defensive medicine," but that's not the whole story. Much of it comes from physicians' almost exclusive loyalty to medical science.
This came home to me recently when a friend told me her story. She'd been caring for her frail and aged mom, two hours from her own home, for weeks. At last things settled down. Driving home, she noticed pain in her back. She realized she might have expected something like that, "…as I'd been carrying a heavy burden." By the time she reached home, the pain was severe enough that she called her physician and requested strong pain medication. He suggested he see her first.
He examined her, agreed that her pain was probably secondary to stress, but--just to be sure--recommended a CT scan. When she took the order slip to radiology, the receptionist said, "Fine, but are you aware this will cost you about a thousand dollars?" My friend hit the ceiling. She tore up the note, called her physician, and said, "We both know I don't need a scan. How about just giving me a prescription?" The doc said, "Fine."
Okay, we can say that was an example of defensive medicine. When I related it to another doctor friend, though, he had a different take. "How old is she?" he asked. "Has she had a bone density test? How do we know this isn't a pathologic fracture, or a bony cancer metastasis?"
"My God," I answered, "those are such zebras." That's actually a medical term, deriving from a time-honored axiom in this biz, "When you hear hoofbeats outside, think of a horse before a zebra."
"Sure," my friend said, "but zebras do show up sometimes."
Thinking about that, I realized that's a standard medical rejoinder. Mention zebras and horses to doctors, and they'll focus on zebras because pulling the strange and rare diagnosis out of the hat is one of medicine's holy grails. We all want to be the diagnostic hero. With no connection to the woman with back pain, my doctor friend wasn't practicing defensive medicine. He was on rounds, demonstrating his allegiance to exhaustive science.
The doc who finally wrote the painkiller prescription (the pain, by the way, is now history) was jarred from his scientific perch by his patient simply reminding him of common sense. Of course, both approaches are valid, and precise circumstances ought to dictate the eventual strategy. That must depend, then, on a full conversation between doctor and patient. I'm gratified that an increasing number of studies are concluding that this crucial relationship--which our obsession with high-tech interventions has steadily eroded--seems to be reviving.