It’s almost impossible to imagine what a Handel opera performance can have been like in London in the 1730s, when Orlando first appeared. The audience came primarily to hear their favourite singers: and these must have been sensational, if not unduly dedicated to the dramatic verities they were supposed to be representing: castrati like Senesino and Farinelli, sopranos like Cuzzoni and Faustina (who once came to blows onstage, presumably trying to upstage one another).

A Richard Bean play is always to be welcomed – he wrote England People Very Nice and One Man, Two Guvnors, two of the most enjoyably rambunctious comedies of recent years – but also with a note of caution. Sometimes, as with The Big Fellah, there's more style than substance (or more jokes than narrative) and that's the case with his 2002 play The Mentalists, being given a West End revival with a huge comedy star making his stage debut.

The Watts Gallery in rural Surrey is a very genteel setting for a show by a figure who for most of his life was denied polite society. Richard Dadd spent 42 years in mental hospitals, first at Bethlem, then Broadmoor.  As one can infer, he was criminally insane, and despite a disarming interest in fairies, his life and work cannot be spun into a happy-ever-after narrative.

Louis Theroux just wants to make good television. This may seem an obvious thing to say of a programme-maker, but many programme-makers concerned with the kind of human interest story that Theroux has made his own, often want to do more than this. They want to understand subject and motive, to get under the skin of a thing, or perhaps somehow resolve an issue. They believe, and sometimes perhaps they may even be right, that this in itself will produce good television, or at least go most of the way there. 

Oscar winner Julianne Moore: the phrase has been a long time coming but it finally came true 10 days ago when the actress, long considered one of Hollywood's best and brightest, added an Academy Award to her groaning mantelpiece of trophies for her work in Still Alice. Is this actually the finest performance yet given by the flame-haired 54-year-old? Probably not (Far From Heaven, anyone?), and Still Alice – an entirely well-meaning venture that inspires admiration more than actual affection – is some way from the most memorable movie to yet showcase Moore's gifts.

But as a Columbia University linguistics professor who succumbs to early onset Alzheimer's, the Richard Glatzer-Wash Westmoreland collaboration tells its sorrowful story with sensitivity if no particular inspiration. Let's just say that as a platform for a performer possessed of generally unerring instincts, Still Alice joins the likes of Monster and Blue Sky among the ranks of trophied Oscar titles that will be remembered primarily for their leading ladies. 

The irony of an academic who has given herself over to the study of human language only to watch her command over her own verbal acumen, and much else, fall away in itself feels familiar. Glatzer and Washmoreland clearly love their theatre (Kristen Stewart, cast true to sullen type as one of Moore and husband Alec Baldwin's three children, here plays a budding theatre actress), and some may find echoes in this adaptation of Lisa Genova's novel with the Pulitzer Prize-winning Margaret Edson play Wit, in which an English professor dying of ovarian cancer clings to such works as Donne's "Death, Be Not Proud" even as death comes to claim her. (Stewart and Moore are pictured above)

And it wasn't quite a decade ago that Julie Christie found herself at the Oscars for playing an Alzheimer's patient in Away From Her (in the end losing the prize to Marion Cotillard's Edith Piaf), though Moore's struggle here feels more fearsome moment-by-moment, not least because the Still Alice filmmakers keep their focus on their leading lady, in effect sidelining Baldwin, Stewart, and some fine actors elsewhere in the cast. (Baldwin is clearly a good luck charm when it comes to winning Oscars for his female co-stars: he was Cate Blanchett's husband in her 2014 turn in Blue Jasmine.)

One watches as Alice searches for a word in public or can't find the bathroom within the privacy of her own home, and it's only a shame that the creative team settle for as pat a choice for poetic citation as Elizabeth Bishop's (admittedly wonderful) "One Art", with its opening line, "The art of losing isn't hard to master." We witness the indignities of Alice unable to tie a shoe on the one hand and calling a daughter by the wrong name on the other. You get the inevitable standing ovation moment alongside a worsening chronicle of the illness-induced privations that exist behind closed doors.

The ending, like much else in the film, is overreliant on an extant source, this time on Tony Kushner's Angels in America, the play that budding thesp Stewart happens to have been working on as her mum's recall gives way perhaps for good. But if Still Alice has to borrow rather too often to achieve its effect, the film is lifted by one of the few actresses out there who can make even the blankest of despair feel entirely fresh.

• Read theartsdesk Q&A with Julianne Moore

Overleaf: watch the trailer for Still Alice