A hobbled, retired NFL football player is addicted to painkillers.

A doctor who has worked closely with the NFL Players Association said the union recognizes that the cycle - first the pain, then the addiction - has become all too familiar among retirees.

"It's a violent sport ... and you can put a lot of work into muscles, but you can't strengthen bones and tendons," said Sidney Schnoll, a doctor and former University of Pennsylvania professor who has consulted with NFL teams as well as the players' union.

Problems go beyond the physical. In a 2007 survey of 1,594 retired NFL players by the University of Michigan Health System, nearly 15 percent reported experiencing moderate to severe depression.

"Retired professional football players experience levels of depressive symptoms similar to those of the general population," the Michigan study concluded. "But the impact of these symptoms is compounded by high levels of difficulty with pain."

The survey said respondents who were rated as moderately to severely depressed were much more likely to have problems with a lack of social support or friendships; the use of prescribed medication, alcohol or other drugs; and trouble with the transition to life after football.

"Here's an interesting catch-22," said Eric Hipple, outreach representative for the University of Michigan Depression Center. "Pain can bring on depression - accentuate it, I should say. But once you're in that cycle of depression, your pain threshold is actually lowered."

Hipple, who spent 10 years playing quarterback for the Detroit Lions, made battling depression his work after his son committed suicide at age 15 in 2000.

"What came out [of the survey] was a lot of pain problems - it seemed like pain was probably the biggest issue," Hipple said. "The transition from football to normal life was huge. Virtually everybody who responded to it said they had some problem with making the transition at some point in time - almost 100 percent."

Former players have testified in Congress about increased rates of bankruptcy, divorce, and even suicide. There are wildly varying figures on the average life span of former players. But studies have shown linemen especially have an increased susceptibility to heart disease.

Schnoll, now the vice president for risk management of Pinney Associates, a health-policy consulting company, said of retired players: "If we admire these people for what they do playing football, we have to develop programs to address these issues, so people don't fall into the depths."

The image of retired players being the guys who finally hang it up as they approach 40 isn't the correct one, Schnoll said.

"If you really look at the longevity of players, it's only three to five years," he said.

Hipple said high-profile players "who can work with their name certainly have a little bit of an advantage," but even the stars typically have a postretirement identity crisis, he said.

When they're done, Hipple said, retired players are years behind on entering the job market.

"The guys who don't have the ability to play off their name . . . ," Hipple said. "The conveyer belt that took them from youth through high school and college all the way to the pros, all of a sudden they're dropped off, and where do you go?"