Stephen Karam’s family drama “The Humans,” which just transferred to Broadway immediately following a short run at the Roundabout’s off-Broadway space, is unapologetically depressing and lacking in narrative. Its pretentious and generic title is also a turnoff. Nevertheless, it makes for a compelling and often terrifying character portrait.

During the course of 100 minutes without pause, a middle-class Scranton family comes together for a makeshift Thanksgiving dinner at the empty duplex apartment that the youngest daughter (Sarah Steele) has just moved to in lower Manhattan with her older boyfriend (Arian Moayed).

Things are not going well for everyone else: the grandmother (Lauren Klein) is suffering from Alzheimer’s, the father (Reed Birney) just lost his job and pension and has recurring back pain and insomnia, the mother (Jayne Houdyshell) is overeating as a result of withheld emotions and the older daughter (Cassie Beck) just lost her longtime girlfriend and is suffering from a severe internal disorder that is disrupting her legal career.

In other words, there isn’t much to be thankful for this Thanksgiving, and none of the problems are resolved or ameliorated by the play’s end.

The end, as Birney’s character is left alone in the darkened apartment, anguished physically and emotionally, is a genuinely cathartic moment of theater, leaving you to wonder: “Why must this reasonably decent guy suffer so much? Am I doomed to the same fate? Can I avoid it?”

“The Humans” is not as appealing as Karam’s terrific comedic dramas (“Speech & Debate,” “Sons of the Prophet”), but Houdyshell’s razor-sharp delivery of her character’s witty responses earns laughs.

Under the direction of Joe Mantello (“Wicked,” numerous new plays), the actors deliver vulnerable, truthful performances while also handling simultaneous action on the two-story set, overlapping dialogue and many silent pauses.