The Glue Sniffer used to haunt our street. Sometimes he would squat, Gollum-like, on the pavement and peer at passers-by. At other times, he would have his head stuffed inside a bag that swirled with toxic fumes, inflating and deflating rhythmically as his throat emitted a gravelly rattle.

For a few years, the Glue Sniffer became a local bogeyman, a gauntlet to be run by passing schoolchildren and university students - his spot was on Old Aberdeen’s High Street, at the heart of the University of Aberdeen campus. He wasn’t there every day, but you would hurry past anyway, just in case he appeared out of nowhere.

Some things never changed: the same spot; the same wide-open eyes, rictus grin and scraggly ginger beard; the same outstretched hand and Pavlovian refrain - “Geez a lain o’ 20p!” - when anyone passed by. My brother was 7 or 8 at the time, and a friend of his claimed to have been chased up the street by the Glue Sniffer. We decided this was a flight of fancy driven by the boy’s fear: the Glue Sniffer’s behaviour might have seemed threatening, but he was never aggressive.

A few years after he first appeared, this troubled soul - who I’m guessing was in his twenties, although it was hard to tell - stopped turning up at his spot. I’ve no idea what became of him.

What had happened in this man’s life that led to him living such a seemingly abject existence, with his identity reduced to his self-harming behaviour?

In his 2005 biography Stuart: a life backwards, Alexander Masters find an ingenious way of jolting readers out of their judgemental attitudes about people like the Glue Sniffer. He introduces us to Stuart, a homeless man in his thirties who is often hard to like because, among other things, he is liable to wield a knife aggressively - on himself and others - and take people hostage.

Masters draws us in, with our distaste for grown-up Stuart’s behaviour often trumping our compassion. Then he tells Stuart’s life story in reverse, from adulthood to his earliest days: we see how a happy-go-lucky child disappeared, after years of abuse at home and in the institutions that were meant to care for him.

We like to think we live in more enlightened times now; that we look beyond troublesome behaviour and try to understand the reasons for it. Professionals of all stripes talk the talk on poverty, mental health and childhood trauma. But how much of this is mere lip service? Do our systems, in education and beyond, really do much more these days to help people whose behaviour jars in polite society?

A report published this week by the Scottish Parliament’s Education and Skills Committee poses some troubling questions. Its analysis shows “little or no improvement in a number of areas”, including: positive destinations for care-experienced young people; employment rates for disabled young people; and employment levels for young people straight out of school.

The committee also fears that workload is getting in the way of teachers’ ability to support pupils, while a separate report says that children with additional support needs are being let down by falling numbers of specialist staff and decreasing services.

In 2018 we’re supposed to have an education and wider children’s services system that doesn’t let anyone fall through the cracks. Yet, the support infrastructure for young people is often still sorely lacking and, in some regards, is getting worse.

We may express more compassion now towards those whose lives are in a downward spiral - but we could do a hell of a lot more to help them in the first place.

@Henry_Hepburn