Every 15 years or so, the American musical veers in a new and unpredictable direction. When it works, it inspires a wave of imitators. Phantom and Les Miz spawned a decade of bombast. Rent added urban flava and moved gay life and issues to the forefront. Something tells me Next to Normal, which debuted on Broadway less than four years ago, is the model for the next wave. Its pop-rock score, by Tom Kitt, won a 2009 Tony, as did its lead actress. Its book, by Brian Yorkey, began as a 10-minute diatribe against the mental health industry but developed into an all-too-believable portrait of a middle-class family in crisis.

We find Diana Goodman waiting up for her teen-aged son while her insomniac daughter Natalie does calculus homework. As her husband Dan sings the next morning, it's "Just Another Day" in workaday suburbia. What we haven't figured out is why Diana's so distracted. She has a better idea than we do, but even her shrink, the ironically named Dr. Madden, can't get a handle on her dysfunction, prescribing one cocktail after another of happy pills. Because yeah: this musical goes there. Diana's mentally ill, and it's unclear whether trauma some years ago brought on these troubles or they already existed, depriving her of the ability to cope.

Now, without relating too much of my own dating history, let's just say I've been in Dan's shoes. The troubles the Goodmans endure - and they are good men and women, trying desperately to be kind and fair to each other - feel disturbingly real (hence the frequent adult language). Justifying bursts of song is always tricky, but this family lives in such a heightened state of emotion that their near-constant singing makes perfect sense. The score seldom gives us the chance to applaud at the end of a number, and that's wise. We're content to observe, never knowing who's the hero, the villain or victim in this sad situation. You'll probably cry. I did. But don't worry, there are also earned laughs, and two kids fall in love. As Ben Brantley of The New York Times observed, you'll "feel everything." It's a wonderful show.

Much of what you'll feel about Next to Normal at Capital Playhouse is admiration for its performers. This production, directed exquisitely by Brian Tyrrell, features a gorgeous lead performance by his wife Jana. Brian also helmed Harlequin's heartbreaking Rabbit Hole a few years ago, and the Goodmans feel much like that same family 16 years later. Erin Snodgrass is outstanding as Natalie. Kurt Raimer's deeply relatable as Dan. Musical director Claudia Simpson-Jones assures me the score's incredibly difficult to sing, but while I did hear some scooping toward pitches, it never broke the dramatic reality sustained by the acting. Friday's house was over half empty. Here's hoping I've convinced you to change that.

CAPITAL PLAYHOUSE, NEXT TO NORMAL, THROUGH FEB. 17, WEDNESDAY-SATURDAY 7:30 P.M., SUNDAY 2 P.M. $28-$39, 612 FOURTH AVE. E., OLYMPIA, 360.943.2744