After an amputation, most patients have a sensation that the limb is still attached and functional. It’s known as phantom limb, and it’s just one sign that the psychological adjustment to losing a limb can be as challenging as the physical adjustment.

In addition to phantom limb, those who lost legs in Monday’s Boston Marathon attack may face post-traumatic stress disorder and grief as they adjust to a new normal.

“I always tell my patients that as hard as it is, it’s a new reality, and the choices are to go into a dark room and close the door or confront the world in that new reality,” said Dr. Alberto Esquenazi, chairman of Einstein Healthcare Network’s Department of Physical Medicine and Rehabilitation and chief medical officer for MossRehab Medical Center in Pennsylvania, who is himself an amputee.

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Often, doctors will hear new amputees say their lives are over. When Dr. Terrence Sheehan, Chief Medical Officer at Adventist Rehabilitation Hospital of Maryland and medical director of the Amputee Coalition hears that, he says, “Nope. It’s changed, and we’re going to help.”

The rehab process involves a team of social workers, psychiatrists, physical therapists, occupational therapists, case managers and nurses. Often one of the most powerful visits in that early stage, Sheehan said, is from a new peer: a fellow amputee.

“When someone who has also lost a limb comes in and says, let me show you how to get back to life, that’s when they can see what life’s going to be,” said Sheehan, referring specifically to the Amputee Coalition’s peer visitation program.

And while runners may be able to handle the physical challenge of rehab and therapy, sometimes the emotional toll is hardest on people who perceive themselves as strong.

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“It can take much longer for them to realize their new reality,” Esquenazi said. “You can imagine that for someone who was running the race or had the ability to be there watching, in an instant their life changed. When you’re confronted with that kind of life-changing event, it can be very challenging psychologically.”Like those injured in war zones, many people who witnessed the scene at the Boston Marathon may face PTSD.

“The shock is wearing off,” Dr. Joseph Shrand of Harvard Medical School said on New England Cable News. “Now the reality is setting in.” Symptoms may include anger, fear, sadness, a sense of confusion — at any time, in any order, he said. That’s in addition to the steps of the grieving process that most new amputees go through, Esquenazi said: denial, why me?, blaming others … and, finally, acceptance.

When they do reach acceptance, patients can usually visualize what their life might be like. Life without a limb can mean a variety of different things to different people. For the elderly, it may be getting to live at home again. For a teenager, it may mean driving to the prom. For a runner, it may mean competing in another marathon. Much more is possible for amputees now than before 1990, Sheehan said.

“Before then, we might have said, OK, you’re done with service, or you’re done working. You’re disabled,” he said. “Now it’s, get back on the plane, get back to climbing, running, jumping.”

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To runners, he’d say, “we have the technology to get you back to your sport.”

In addition to, or perhaps because of, the advances in prosthetics that allowed Oscar Pistorius, the Blade Runner, to compete in the Olympics, and allows others to run marathons, people’s perceptions have changed.

“People are much more comfortable showcasing their apparatus without qualms,” Esquenazi said.

Jeff Glasbrenner, who has been an amputee since age 8, was finishing the marathon when the bombs went off.

“I wish I could reach out to the people who lost a leg,” he told the New Republic. “I’d love to run a race with them.”

Even with all the technology in the world, adjusting to life without a limb will be challenging. For many amputees, the sensation of a phantom limb never fully goes away, and some experience excruciating phantom limb pain. But experts suspect that people such as Glasbrenner may ease the transition.

“This is going to be a process — it’s not a single episode,” Esquenazi said. “But with time, and in stages, they are going to succeed. We’re going to stand behind them and try to help these individuals function at the highest level they can. They have the emotional support of the country behind them.”