The family of Derek Boogaard has filed a wrongful-death lawsuit against the National Hockey League.

It contends that the N.H.L. is responsible for the physical trauma and brain damage that Boogaard sustained during six seasons as one of the league’s top enforcers, and for the addiction to prescription painkillers that marked his final two years.

Boogaard was under contract to the Rangers when he was found dead of an accidental overdose of prescription painkillers and alcohol on May 13, 2011. He was 28. He was posthumously found to have chronic traumatic encephalopathy, or C.T.E., a brain disease caused by repeated blows to the head.

“To distill this to one sentence,” said William Gibbs, a lawyer for the Boogaards, “you take a young man, you subject him to trauma, you give him pills for that trauma, he becomes addicted to those pills, you promise to treat him for that addiction, and you fail.”

The N.H.L., through a spokesman, declined to comment Sunday.

In 55 pages of detailed accusations, the suit does not seek specific damages to be awarded to Boogaard’s parents and four siblings. It asks that a trial jury determine “a sum in excess of the minimum jurisdictional limit” for each of eight counts in the suit.