In Next to Normal, members of the Goodman family — whose lives revolve around the moods of the bipolar mother, Diana — travel an arc from chaos and denial to the realization that "the price of love is loss."

This great contemporary rock musical won a 2009 Tony Award for its score and orchestrations and, more unusually, the 2010 Pulitzer Prize for drama. Composer Tom Kitt and lyricist and librettist Brian Yorkey stretched the boundaries of the form in their alternately unsparing and poetic depiction of the ravages of mental illness. (Alice Ripley also took home a Tony for her performance as Diana.)

For West Chester's ambitious Resident Theatre Company, director Kristin McLaughlin Mitchell and music director Corey Everly have assembled an outstanding cast of singing actors. This is an uncommonly sympathetic version of Next to Normal — the fifth production I have seen — and it is often thrilling.

Every character — including father Dan (wonderfully played and sung by Galen Murphy-Hoffman), daughter Natalie (a wrenching performance by Chelsey Ristaino), brother Gabe (Alex Kunz), boyfriend Henry (Christopher Sheehan), and even the two floundering psychiatrists (John Wilkening) — is trying his best to make it through "just another day."

At the center of this suburban maelstrom is Diana (Nikki Van Cassele), whose official diagnosis is "bipolar depressive with delusional episodes." In common with many bipolar patients, Diana wants at times to ride the surfboard of her moods, and has trouble finding a mix of medications that won't deaden her. "I Miss the Mountains" is her hymn to mania, while "You Don't Know" details the terrors of depression ("Do you read obituaries / And feel jealous of the dead?").

Van Cassele, reprising the role she played under Mitchell's direction at the Cape Rep Theatre in 2013, is equal to the part's vocal demands. But she lacks Ripley's wryness at times– the show has its share of humor, which this production sometimes slights — and favors broad gestures over more subtle emotional shadings.

Of the two women, Ristaino's teenage Natalie — whose relationship with the ever-faithful Henry echoes Diana's youthful romance with "the steadfast and stolid" Dan — seems the more anguished, the more real. Compared with her "superman" brother, Natalie feels at times like "the invisible girl," the less-loved child.

As Gabe, Kunz is poignant and energetic. But his anthem, "I'm Alive" ("I'm your wish, your dream come true / And I am your darkest nightmare too"), telegraphs the role's complexity, and I've seen Gabe played with a more overtly threatening edge.

Brian Dudkiewicz's set, with its triple-outlined house and risers illuminated by Lily Fossner's neon lighting, underlines one of the show's principal themes: the struggle to find "a light in the dark."

Quibbles aside, this is a profoundly moving evening of theater. Next to Normal is a brilliant take on the ties of family, the endurance (and limits) of love, and the mysteries of mental illness, and this production does it justice.

Theater Review

Next to Normal

    • Through Oct. 15, presented by Resident Theatre Company at the Uptown! Knauer Performing Arts Center, 226 N. High St., West Chester, Pa.

    • Tickets: $25-$53