Dysfunctional suburban life isn’t exactly a new subject, and period coming-of-age stories even less rare, but Derick and Steven Martini combine the two to reasonably good effect in “Lymelife.”

The movie is set on Long Island in the late seventies (though, to tell the truth, the mention of both the Iranian hostage crisis and the Falklands conflict confuses the chronology a bit), and centers on Scott (Rory Culkin), a fifteen-year old kid with eyes for his neighbor and long-time chum Adrianna (Emma Roberts), who’s slightly older and interested in more mature boys.

Scott’s older brother Jim (Kieran Culkin) is a soldier home on leave after basic training, before being deployed, and takes vengeance on a schoolyard bully who’s just pummeled Scott. But the greater household problem is with their parents. Mom Brenda is intensely unhappy, pining after their old home in Queens, and estranged from Dad Mickey (Alec Baldwin), who spends virtually all his time working on a subdivision that he hopes will be a goldmine. He’s also having an affair with his assistant Melissa (Cynthia Nixon), Adrianna’s mother, whose husband Charlie (Timothy Hutton) is suffering from lyme disease. He pretends to be going to the city each day, but actually spends his time lurking in the basement or stalking deer in the nearby woods.

Plot, frankly, isn’t the picture’s strong suit. What “Lymelife” is concerned with are the evolutions in the relationships among the characters, with Scott and Adrianna growing closer, though with speedbumps along the way, and eventually having an intimate bedroom encounter that’s convincingly clumsy, while their parents work their ways through their mutual entanglements. The titular disease, and the unhappy events that keep intruding on the character’s consciousness from outside their small orbit, act to situate the local troubles within a larger world of global problems. The final minutes build considerable suspense about whether things are about to get even worse, and it’s appropriate that the issue is left unresolved. But some viewers are likely to feel as cheated by the ending as they were by the close of “The Sopranos.”

The film scores, though, in the genuineness of its environment (kudos to production designer Kelly McGehee, art director Matt Munn, set decorator Kelley Burney, costumer Erika Munro, and cinematographer Frank Godwin), in the Martini brothers’ sharp writing and Derick’s sensitive direction, and the strong performances across the board. Rory Culkin exudes shyness and vulnerability, and carries off even the scenes in which he poses and practices bits of dialogue in front of a mirror, and Kieran is dead on as his exuberant older brother, while Roberts has a Lolita-like quality as the object of Scott’s obsession. The parents are excellent two, with Baldwin again showing how far he’s developed as a character actor and Hutton convincingly gaunt and tortured. Hennessy, meanwhile, manages Brenda’s radical mood swings well, and Nixon does likewise with Melissa’s.

“Lymelife” may not do anything radically new, but it offers enough twists on familiar territory to be worth a visit.