A social comment drama in musical guise is not encountered every day of the week, so I was intrigued to see whether the material and form of STOP worked effectively in tandem. This student show written and staged by current and recent Oxford students was seen at the BT Studio in January and is now, with just one cast change, en route to Edinburgh where it will play as the OUDS' offering to the Fringe.

Mental Heath services seem to have been languishing as the Cinderella branch of the NHS ever since I can remember from the late 60s, and no doubt for decades before that. I was going to suggest that the overt stigma of the plethora of conditions may be to some extent on the wane until I read on Friday of Donald Trump’s new communications director having attacked the White House chief of staff for being “a paranoid schizophrenic”. Drama can make a useful contribution in drawing attention to the struggles that can lie behind the face individuals present to the world. There was a hearteningly sizeable audience of 100 or so at the Pegasus, with an awareness Q&A session before the show, and SANE Mental Health Charity was raising money for its activities and specifically its Black Dog campaign, in the foyer.

The set was a wood (painted black, perhaps a reference to the time-honoured 'black dog' image for depression) and perspex bus shelter housing a couple of red metal benches, and this housed, collectively and severally, our cast of four as they waited for a bus, though until the very end they might just as plausibly have been waiting for Godot for all the sense there was of any bus ever materialising, despite the presence of timetables and map pinned up at the shelter. Our four characters stood in front of us and disclosed their mental health problems either directly or, particularly in the case of Lewis, a personal trainer and 'life coach', by degrees as the carapace of his personality peeled away like the thin layers of a Spanish onion. Eoghan McNelis, seen by me lately in Guys and Dolls and Anna Karenina, handled with aplomb Lewis' revelations as we got to understand that beneath the brash jock there lay a fragility of confidence, abraded by years of foster care, with the consequence that he was determined to fix his wedding day for Christmas, a time of year that in times past he had learned to dread.

The time line of the drama jumped about a bit but without confusion from present to the reported past, and even, in an effective aside, ahead to 2028. But in the basic structure of the scenes there lay, I thought, something of a problem. There was just a little too much didactic speechifying as the characters identified first their presenting and then underlying conditions – panic attacks, agoraphobia, rotten childhood, alcoholism and so on. The living drama might have been better served by teasing out these aspects of character by means of interactive dialogue. The rhetoric risked placing a barrier before us in our wish to believe fully in these characters as living, breathing entities rather than for what they represented.

The music, comprising both sung dialogue and then a number of songs, complemented the theme and of course relieved what could have been a heavyish experience. I thought Asking Questions, How Do We Get On? (both deservedly reprised) and Treat Yourself were the highlights, all catchy numbers that deserve an independent life beyond this show. The off-stage band (piano, bass, guitar, cello, violin, viola) was accomplished though occasionally the piano was over-loud and emphatic, giving a slight impression of competing with rather than accompanying our cast whose singing lacked for nothing in either volume or finesse.

I especially liked Gemma Lowcock's Chloe; new to the cast, with her ever-present turquoise 'trolls' plastic bag she presented as a fast-talking but vulnerable figure, at one time red-faced with emotion and displaying tortured body language, and I was sorry that her character rather disappeared from the play after a strong first half. Jack Trzcinski, whom I remember meeting at David Hare's Skylight in June, was an impassioned would-be dancer, struggling to make the most of his nascent talent. Annabel Mutale Reed, writer of the book and lyrics, and also co-director with Olivia Munk, was a touching Martha, low in confidence but fighting hard to connect with her friends. To Lewis: "you're good and kind and a really good kisser!" What a sterling effort Ms Mutale Reed has put in for this cause.

A thoughtful, buzzing show that deserves to be seen in Edinburgh both on artistic merit and for its important material.