Next to Normal, with book and lyrics by Brian Yorkey and music by Tom Kitt, follows Diana, a bipolar depressive with a dead son, a rock star psychiatrist, a daughter she describes as “a freak” (and her stoner boyfriend)… and Dan, her husband.

When it was on Broadway during 2009-11, the production controversially won the Pulitzer Prize, and also gained a cult following on YouTube and Twitter, before closing in January 2011.

Bipolar depression is not an easy topic to write a musical about – and the pain felt by many of the characters is scarily real. The various attempts made to manage Diana’s condition correspond to real life treatments for bipolar II, and watching each of them try, and fail, to heal “the cut, the break… in your soul” is terrifying to watch.

The addition of Diana’s son Gabe into the mix lends something of a sinister, seductive aspect to the show. Their scenes, culminating in Diana being led to attempt suicide, are made more worrying by the fact that it isn’t until the middle of the first act that we even find out he’s died, and it becomes clear just how far Diana’s psychosis has progressed.

This is not to say that the musical is altogether depressing. Diana’s daughter Natalie and her boyfriend, Henry, have some incredibly sweet moments as he tries to pull her out of her own spiral towards substance abuse and depression. Their arc, ending as it began, with the word “I could be perfect for you”, is tinged with a bittersweet acceptance of the other.

Even Dan and Gabe find a resolution of sorts. Natalie and her mother reconcile, and we are left with a more balanced, if disparate, family, searching for “the light in the dark”.

Is _Next to Normal _misogynistic? Maybe. It’s certainly true that Dan is presented as a sympathetic figure and Diana as something of a home wrecker. Natalie is similarly seen to be unable to handle things without the strong hand of Henry. Even the end of Dan’s arc relegates her to the status of a caregiver. And it fails the Bechdel Test. Which, given how much else Natalie and her mother might have to talk about, is quite upsetting.

The music, though, is wonderful. It doesn’t have the richness of Bernstein, nor does it require the vocal gymnastics required for works by Jason Robert Brown. Despite this, it stands up as one of the strongest examples of a rock musical score I have heard to date, making it a worthy winner of the 2009 Tony for Best Original Score.

The show taps elements of the human experience that we don’t get to see all that often, filling a void left unattended since Jekyll and Hyde was released in 1997. It’s not perfect – it’s not normal – but it opens out the scope of musicals beyond what’s been done before and since. Yorkey and Kitt have done well with Bring it On, the musical based on the little cheerleading squad that could, and If/Then, which starred Wicked and Frozen’s Idina Menzel. Maybe they could use some of this success to launch a full British production? Only time will tell.