From mental illness and adultery to football obsession and competitive dance, “Silver Linings Playbook” follows a wily and winding path that consistently defies expectations.

Serving as both writer and director in adapting Matthew Quick's novel, David O. Russell has developed affectionately fleshed-out characters in a deeply steeped sense of place: working-class Philadelphia.

Bradley Cooper and Jennifer Lawrence both give inspired performances that allow them to play against type as the unlikely couple at the center of this romance. Cooper sheds his charisma and slick good looks to star as Pat Solatano, a teacher who's just been released from a mental institution at the film's start. He suffered a breakdown when he caught his wife in the shower with one of her co-workers. Now, having lost his marriage, home and career, he hopes to start over — and that starts by moving back in with his parents.

Robert De Niro does some of the best work in recent years as Pat Sr., a hardcore Philadelphia Eagles fan whose game-time superstitions have long since developed into full-blown obsessive-compulsive disorder.

Pat tries to take all the right steps to further his recovery — attending therapy sessions with the no-nonsense Dr. Patel (a very funny Anupam Kher), running every day — but he just can't accept that his wife wants nothing to do with him.

Then one night, at a small dinner party thrown by old friends whose own marriage isn't in the best shape (John Ortiz and Julia Stiles), Pat meets Tiffany (Lawrence). Recently widowed after the death of her police-officer husband and having been fired from her job, Tiffany is equally at sea. And like Pat, she has no internal censor, so this first meeting is full of quick, sharp banter and spectacularly inappropriate observations.

Following intensely serious roles in “Winter's Bone” and “The Hunger Games,” it is such a joy to see yet another facet to Lawrence's talent. She's already demonstrated a maturity beyond her years, but “Silver Linings Playbook” allows her to let loose and have a little fun while still maintaining a dramatic integrity.

On the flip side, Cooper gets a rare chance to show his dramatic side. There's a mania to his performance here as his character strives to convince himself of his capacity for happiness, but also a raw dark side.

Yes, “Silver Linings Playbook” wraps up in the most traditional of rom-com settings: on stage in front of a huge crowd of strangers who will witness Pat and Tiffany's love blossom for the first time. But the route it's taken to get us there is so inspired, not only will you not mind — you'll find yourself charmed.

TITLE: “Silver Linings Playbook”CAST: Bradley Cooper, Jennifer Lawrence, Robert De NiroDIRECTOR: David O. RussellRATED: R for language and some sexual content/nudityGRADE: ★★★★ (out of 5)