“What a joke” and “I want to die” are appropriate refrains for How to Make Friends and Then Kill Them, a potent blast of tragicomedy now playing at the Rattlestick Playwrights Theatre. On a stage wreathed with asbestos and alcohol, Ada (Katya Campbell) and Sam (Keira Keeley) live a life of fantasy and delusion, their childhood unmarred by adult supervision thanks to a perennially absent, alcoholic mother. Ada dreams of success as a glamorous actress and performs self-penned paeans to her own beauty (or “monologues,” as she calls them). Sam, harboring a love for Ada that seems more sapphic than sororal, obeys her sister’s every command while sneaking in attempts to draw her and touch her hair.

This dysfunctional duo turns trio when Ada meets Dorrie (Jen Ponton), a wide-eyed girl tipping over with ailments and anxiety. Sam is fiercely territorial, but no matter: Dorrie’s desperate need for friendship is strong enough to endure both Sam’s jealousy and Ada’s raging selfishness. The three’s codependency carries them from childhood to adolescence to early adulthood, their bonds tightened by failure and thoughts of suicide. Only when the ugly realities of being a full-blown grown-up set in do the girls contemplate breaking with each other’s company.

The results are comical but never lighthearted. Even in the beginning, when the infantilism of the girls is at its funniest, there is an unsettling undercurrent. Self-administered bruises and booze are among their playthings and a heavily ominous cellar door, leaking an eerie current of air, looms over the proceedings. Their lives progress in repetitive cycles, each revolution becoming more painful than the last. Ada attempts professional acting and Sam tries writing a graphic novel but rapid fire games of patty-cake and declarations of “sock-bracelet” sisterhood continue. All three girls wish to break free of the cycle by the most drastic of means. When Sam says she wants to die, Dorrie happily exclaims, “I want to die, too!” And this revelation leads them briefly back to happiness.

The cast is admirably assembled. Ms. Campbell excels at the air-headed egotism, the casual cruelty, and the whimpering vulnerability all required to make Ava anything more than a petulant caricature. Guffaws and heartache follow Ms. Ponton’s breathless exhilaration at having any friends at all. But if there is a standout performance in the lot, it is probably Ms. Keeley as Sam, who has the unfair advantage of portraying the play’s most nuanced character. She manages to maintain the sexual thread that strings together Sam as both a limb-thrashing little girl and a brooding adult artist.

The play does lose some efficacy when the humor fades completely. Ada’s trip to New York City and Dorrie’s ultimate fate push the punishment to extremes that seem as juvenile as the girls themselves. But overall, Halley Feiffer’s rendition of sustained immaturity and doomed ambition has quite an impact. A few of the audience members left visibly shell-shocked, possibly wondering (as the girls never did) whatever happened to their lives.

How to Make Friends and Then Kill Them runs through December 14th at the Rattlestick Playwrights Theater.  224 Waverly Place  New York, NY.  1 hour 30 minutes.  No intermission.