Recovery depends on honesty, but Emma – not her real name – lies for a living. Duncan Macmillan’s searing play, getting a well-deserved West End transfer from the National, complicates the familiar story of addiction and rehab by making its protagonist an actress. The dissociation, self-delusion and pathological deceit that frequently accompany the disease are reframed by this sometimes dizzying metatheatricality, which, in Jeremy Herrin’s vivid Headlong staging, plunges us into the abyss.

Hurray, the two-part epic wizard-fest Harry Potter and the Cursed Child lands in the West End this summer, and its playwright is the ever-versatile Jack Thorne (who also successfully adapted the vampire romance Let the Right One In for the stage). But audiences who’d like to enjoy Thorne at his thorniest, rather than most Rowlingesque, might prefer to take a look at this, his 2015 two-hander about a couple and their loss of a child. It’s a Hogwarts-free zone and its main emotional fuel is horrific loss coupled with courageous honesty. Strictly for adults only.

Although everyone agrees that Sarah Kane was one of the most influential British playwrights of the 1990s, revivals of her work have been few and far between. Now, at last, some 17 years after her suicide at the age of 28 in 1999, our flagship National Theatre has finally decided to stage one of her best works (artistic director Rufus Norris, thank you). But although she became infamous for the media-fuelled scandal and atrocity-fest aspects of her work, subsequent reconsideration suggests that her main theme was nothing less than romantic love.

"One... Two... You know what to do": that coolly delivered rehearsal intro from a trombonist called Cutler (Clint Dyer) could serve as a synoptic appraisal of the simply overwhelming National Theatre revival of Ma Rainey's Black Bottom. The play in 1984 launched the late August Wilson on to Broadway, where I first saw it, and here announces itself as a bellwether achievement in artistic director Rufus Norris's still-young National Theatre regime and as, very possibly, the finest Ma Rainey yet.

Say what you will about London theatre during 2015, and by my reckoning it was a pretty fine year, there certainly was a lot of it. I can't recall a year that brought with it a comparable volume of openings, not least during September and December, this year's pre-Christmas slate of major press nights roughly double the same time period in 2014. And as proof that people were actually attending the stuff on offer, empirical evidence as ever was the best guide.

Widely hyped as “an Alice for the online generation”, and “a coming-of-age adventure that explores the blurred boundaries between our online and offline lives”, this version of Lewis Carroll’s Wonderland stories is advertised with a poster that shows a Cheshire cat whose smile is more drug-addled rictus than quizzical grin. On the other hand, the team behind the show features three creatives who should be working at the top of their game: Britpop legend and opera composer Damon Albarn, playwright and scriptwriter Moira Buffini and National Theatre supremo Rufus Norris.

The great Caryl Churchill careers down a blind alley in Here We Go, and the results aren't pretty, especially within the cavernous confines of the National Theatre's Lyttelton – this writer's second play this year at that address. A 45-minute triptych about death that gets worse as it goes on, the play put me in mind of the American critic Walter Kerr's famous remark about Neil Simon not having an idea for a play but writing one anyway.

A lot of people are going to be enraged, frustrated, or confused by Evening at The Talk House, and in the authorial world of Wallace Shawn, wasn't it ever thus? This is the playwright who gave pride of place to a softly-spoken fascist in Aunt Dan and Lemon and challenged his audience's complacency directly with The Fever, so if I say that his latest play is of a piece with his earlier ones, that is intended as high praise, indeed.

Do scandals have a sell-by date? When it comes to sex and politicians, the answer is no. The tabloids, and the news-hungry public, still seem to relish a good story about a powerful man who is caught with his trousers around his ankles. So Harley Granville Barker’s Waste – first put on in 1907 and then rewritten some 20 years later – is ostensibly a highly relevant drama of a personal tragedy in which our characteristic national mix of prurience and puritanism gets a longwinded airing. Certainly, the plot is instantly recognisable.

This "mockumentary" concerning the play The Curious Incident of the Dog in the Night-Time was incredibly well-intentioned and unintentionally baffling. It operated on so many levels at once that the viewer could all too easily keep falling through the cracks. Was it about the wonderfully successful play and its productions, the novel that inspired it, or, in the real world, children and adults on the autistic spectrum, and their interaction with society?