On August 1, just 10 days before Robin Williams's suicide, the brilliant Glasgow-based performance artist and mischief-maker Ian Smith took his own life, following a two-year battle with deep depression.

For those of us who knew and loved Smith, his death has raised profound and troubling questions about how our society, and we as individuals, relate both to mental health matters and to suicide.

Such questions are not answered, rather they are deliberately and powerfully compounded, by Lippy, Irish theatre company Dead Centre's contemplation of a real-life suicide pact.

In 2000, in Leixlip, County Kildare, four women (83-year-old Frances Mulrooney and her three nieces, 51-year-old twins Brigid Ruth and Catherine, and 46-year-old Josephine), barricaded themselves in their rented home and starved themselves to death. When their landlord discovered their corpses, there were few clues, besides some fragments of unsent letters written by Brigid Ruth, as to why they had decided to die.

Lippy, written and devised by Dead Centre founder Bush Moukarzel, explores the limits of our understanding of the women's deaths. It also ruminates refreshingly on the very particular powers of theatre in relating to such events.

Gone is the tedious replication of journalistic techniques so beloved of much documentary theatre. In its place, through, for example, a bleakly comic exploration of the imperfect role of lip reading in the police's efforts to discover the motivation for suicide, we are invited to experience with the theatre artists not the deciphering of meaning, but a mutual meditation on the absence of meaning.

At one point, in which the three younger women are represented as backing singers while the lip reader/actor mouths the words of the song Crying In The Chapel, one fears that the show's regard for its own self-conscious techniques has overtaken its respect for the women. That fear is allayed, however, by the Beckettian poetics with which this deep and moving theatre work concludes.

In riverrun, another excellent Irish production at the Traverse Theatre, the poetics are not Beckettian, but, rather, from Beckett's great mentor James Joyce. Dramatist and actor Olwen Fouéré has adapted the voice of the river in Joyce's Finnegans Wake into an extraordinary theatrical monologue, which she then performs with breathtaking vocal and intellectual dexterity and physical vitality.

Imagine Dylan Thomas's Under Milk Wood, shorn of the specifics of its various characters, its energy and humanism collided purposefully with Lucky's great monologue in Beckett's Waiting For Godot (albeit that Finnegans Wake precedes both), and you might begin to gain a sense of Fouéré's exceptional piece. Standing barefoot, wearing a simple, grey suit, speaking into a microphone, cutting her metaphorical way through the sand on the floor, the actor negotiates with deceptive ease an extraordinary torrent of language.

From treacle black, yet forgiving, Joycean observations to playful words and phrases, invented for the pleasure of their sounds and their implied meanings, Fouéré flows with the go (as Joyce might have written). She is, at one moment, movingly and meaningfully contemplative, knocking, for herself and for all of us, at death's door. At another, gleefully animated, the very image of the most sensual, life-loving of Joyce's characters.

In Beckett's Godot, Estragon observes that Pozzo is "all humanity". The same might be said, and more accurately, of Fouéré in this brilliant reinvention of Joyce's river, as she evokes its endless journey between birth and death.

Remaining in Ireland, but in the western vernacular famously beloved by JM Synge, is City Theatre Dublin's charming and hilarious production of The Matchmaker at Assembly George Square. John B Keane's play (originally titled Letters Of A Matchmaker) evokes more innocent times when single people of a certain age might employ the services of an observant individual with a talent (or not, as the case may be) for putting one and one together and making, as the titular matchmaker Dicky Mick Dicky O'Connor says, "one".

Played beautifully by Irishman Jon Kenny and Australian actor Anne Charleston (best known as Madge Bishop in Neighbours), the piece evokes a wonderful panoply of characters. The persistent Fionnuala Crust, dissatisfied with the bedroom performance of her new spouse, demands her money back, with menaces. The Honourable Claude Glyn-Hunter is after younger flesh, of either sex, and brings Dicky McDicky's trade into disrepute with his errant behaviour in the snug of a pub in County Limerick. It's all touchingly funny, sympathetic stuff, brought splendidly and vividly to life. An unalloyed Fringe treat.

Back at the Traverse, dealing in a very different strain of humanism, is Chris Goode's resonating monologue Men In The Cities.

Written, with self-allusion, against the backdrop of the suicide of a young gay man and the very public, very brutal murder of British Army soldier, Fusilier Drummer Lee Rigby, Goode's self-performed narrative might be considered a companion piece to Simon Stephens's impressive 2008 play Pornography.

Like Stephens's work, Goode's monodrama picks up the shards of broken reality we are offered by the purveyors of postmodernity and attempts to reassemble them. The pieces rarely fit, of course, but sense and senseless seep through the gaps.

Sexual anxiety, self-loathing and distorted filial love emerge in the midst of a maddening, postmodern confusion. The realisation that Rigby's murderers, Michael Adebolajo and Michael Adebowale, were motivated, in part, by righteous anger explodes like a cluster bomb. In fact, that's what Goode's play (and his performance) is: an explosion of hundreds of little personal and political bomblets.