Pat is curiously confident and upbeat for a man just released from a mental hospital and under a restraining order from his wife. That’s because he’s determined to repair the damage he’s done to his life and surprise everyone by moving ever onward and upward. His motto is, “Excelsior!”

At the top of his priority list is rebuilding his marriage with his wife; after they split, he beat up her new boyfriend, but what’s past is past. Pat (Bradley Cooper) assures his parents, Pat Sr. and Dolores (Robert DeNiro and Jacki Weaver), that all will be well. They’re not so sure. One of the charms of “Silver Linings Playbook,” the screwy comedy by David O. Russell, is how Dolores is a sane and caring woman and has had long experience in dealing with compulsive behavior, because her husband is a fanatic fan of the Philadelphia Eagles.

Pat Jr. in desperation is drawn toward Tiffany (2010 Oscar nominee Jennifer Lawrence), a young widow in the neighborhood.

People call her a slut, and she agrees. She’s pissed off about Pat because he continues to obsess about his ex-wife.

Tiffany thinks she and Pat should have sex. Pat objects. He doesn’t want to be unfaithful to his ex-wife. We realize Pat doesn’t have a chance. This all builds up into a classic screwball comedy situation in which two bets are inspired — one involving an Eagles-Giants game and the other involving a ballroom dancing contest that Tiffany has forced Pat to join her.

How these bets play out I will not hint.

One of the ingenious and sort of brave accomplishments of Russell’s screenplay is the way it requires both father and son to face and deal with their mental problems and against all odds finds a way to do that.

We’re fully aware of the plot conventions at work here, the wheels and gears churning within the machinery, but with these actors, this velocity and the oblique economy of the dialogue, we realize we don’t often see it done this well. “Silver Linings Playbook” is so good, it could almost be a terrific old classic.