Colleagues ponder Patrick Kennedy’s future, praise work ethic

Now 21 years later, he’s doing something that would have been unthinkable to an earlier generation of Kennedys, ending his political career in midlife. With this decision, Patrick Kennedy relinquishes a chance to carry on the Kennedy legacy in Congress; he also, colleagues say, escapes a poisonous political environment that tested not only his career but also his health.

While his father, the late Senator Edward M. Kennedy, survived several damaging personal and political battles and often found strength in the spotlight, the younger, more sensitive Kennedy struggled in his battles with bipolar disorder and alcohol abuse. Patrick Kennedy twice entered rehab for his addictions after entering Congress.

The death of his father in August deprived Kennedy of not only his parent and mentor, but also his emotional support system. And unlike the senator, who continued to work even as he battled a fatal brain tumor, the Rhode Island representative would perhaps do better, colleagues said, in another Kennedy family role, that of a private-sector advocate for the mentally ill.

“Not having Ted there didn’t in any way reduce the level of energy and commitment to the issues,’’ said US Representative William Delahunt, a Quincy Democrat who is close to the Kennedy family. But Kennedy’s decision not to seek reelection makes sense to “everyone who has had the experience of the loss of a friend or parent, whose companionship and encouragement and support and sense of humor made a difference in their lives.’’

“There’s a sense he’ll prosper in a different environment,’’ Delahunt added.