Ironically, his fingers looked like cigarette butts. They were black and chalky at the tips and then tan through his knuckles to his hands. A couple was capped by long yellow fingernails, shooting out like stalks of hay, bending in different directions.

A few other fingertips had already fallen off, leaving behind stumps he could barely flex or wave.

I sat down and asked what he knew about his disease.

“I’ve Googled it,” he said. “It’s rare. Caused by smoking.”

Mr. X has a disease I never thought I’d see outside of a test question — a disorder in which the small vessels of the hands and feet become inflamed and blocked by blood clots. When a clot forms in the vasculature, the bloodstream halts. Everything beyond the obstruction, muscles, and tissues, begins to die without their blood supply.

Mr. X’s fingers were dying, and several were already long dead.

He asked me for something to drink, and I handed him the styrofoam cup from his bedside table. He clasped it between his two open palms, and took big gulps of room-temperature water.

He told me that when it first started, years ago, it was only on one hand. “So I started smoking with the other,” he said.

Later, he learned that the problem wasn’t actually from touching cigarettes, but from inhaling their smoke into his bloodstream. That explained why his toes began to turn black too, sparking an electric pain through his heels.

I asked how he gets around, and he told me that he places his knees or elbows on two milk crates and shuffles along. As he talked about his disease and about his life in a homeless encampment, I wondered if I had ever driven past his tent under an overpass.

I imagined that if I saw him on the streets, I would’ve stared at his hands and kept my distance. But in this room, I held his gaze as he told me about his girlfriend and his neighbors and their tiny dog with a big bark. He told me about his possessions, a couple of watches and electronics, that he worried would be stolen by the time he was discharged.

Mr. X had been brought to the hospital by the police under a psychiatric hold he did not actually warrant. He was willing to stay for his care, and a psychiatrist lifted the hold. My team, a group of internal medicine doctors, had assigned me to help manage his care. After meeting Mr. X, I called the vascular surgeons for their input, and helped place the orders for blood draws and imaging tests. Then, I went back to his room.

“Have you ever tried to quit smoking?” I asked.

“No way,” he said.

I explained that, while we could try to reduce his pain, the only thing that would stop the progression of his disease was to give up smoking entirely. I offered him nicotine patches and gum, explaining that they’d help him quit by lessening his cravings. When he refused, I explained again.

“It’s not just the craving,” he said. “I know myself. As soon as I’m out of here, I’m gonna smoke. Only half the problem is physiology; the other half is in my head.”

I was struck by his use of the word physiology, and my gut instinct was to tell him that there’s nothing more than the physiology. What’s “in his head” boils down to a host of neurochemical signals that keep him coming back to pack after pack. I wanted to tell him again that we have medicines to suppress those signals, and to stop him from smoking until he’s lost every last finger.

But my instinct to keep pushing was wrong, and I knew it. People don’t change behaviors like smoking at someone else’s insistence — they have to want the change themselves. No amount of repetition or motivational technique would get through to him at that moment. And he was right — suppressing his cravings was only half the battle. It wouldn’t even begin to touch the real factors — the isolation, the instability, and the fear — that underlie his need to reach for a cigarette. Physiology is only a way to explain how the body behaves. It doesn’t account for what drove us toward those behaviors in the first place.

So I stopped myself from pressing him and said goodbye for the day. To brace myself against disappointment, I reasoned that only Mr. X knew what it felt like for his fingers and toes to crumble, causing excruciating pain and costing him his mobility — in a world where mobility is tied to safety. And he understood exactly what he needed to do to halt his disease. He just declined to do it. In a sense, he’d made the most informed decision possible.

But my reasoning was accompanied by overpowering doubt. What is an informed decision in the context of an addiction? I wondered. Did I really do the right thing by stepping away at that moment, or did I completely fail him by giving up far too soon?

Tomorrow is a new day. Will it hurt to try again?

Orly Farber is a medical student who blogs at Scope, where this article originally appeared.

Image credit: Shutterstock.com