It has taken four novels and six or seven years but Doug Johnstone finally considers himself a writer.

He's had other jobs, other titles. Journalist. Singer. Songwriter. Nuclear physicist. Husband. Father. Some of those he's still working at but now his fourth novel, Gone Again, is about to be published he is happy to use the "w" word when it comes to describing what he does.

"I say to people I'm a writer now. That took three, maybe four novels to say that to people at a party," he tells me. We're sitting blowing on our hot soup in the Skylark bistro in Portobello, the place he lives with his wife Trish and their two kids. Outside a wind that seems to be blowing directly from Siberia is cutting people in two. In here we're worrying away at what he does.

"Probably still half of my earnings aren't from writing fiction," the 42-year-old says between mouthfuls of chilli soup. He's done a bit of teaching, he says, and still does some journalism. "I've got four or five part-time livings that add up to the mortgage."

But it's the novel writing that is now his first calling. Johnstone is one of the current breed of Scots noir writers who have emerged in the wake of Ian Rankin and Denise Mina. But unlike such contemporaries as Stuart MacBride and Gordon Ferris, he's not really interested in whodunnits or Scotland's mean streets. Gone Again offers a much simpler proposition. A man waits for his wife to come home from work. She doesn't. While he looks after their child he starts to worry. What if something has happened? When she doesn't turn up the next morning he's sure of it. Reading it is like being punched in the gut with knuckedusters. You know what this man is going through.

The book is an investigation of the primal fears of any father or husband (or wife or mother). It was devised by Johnstone while walking the very streets that appear in the book. Johnstone likes to stick close to home – geographically and psychologically. "The best writing asks you what would you do if your wife was late one night and you phoned her work and they told you she'd left. It's just the mild everyday terror you get."

It's just that in the case of Gone Again the everyday terror turns out to be true. "I cannot be bothered with there's a dead boy on page one, there's a fixed number of red herrings and there's a whole bunch of suspects. I get quite bored with that. I'm more interested in the psychology of the people committing the crimes or caught up in the crimes. That's a personal preference."

In Gone Again the result is a stripped back, spare read that roars along. There is no meandering around Portobello. It goes direct to its destination. "I can't read long books. I don't know if having kids has ruined my attention span or social media has rotted my brain but I can't abide long passages of description or aimless dialogue. There's a real craft in conveying a situation in as few words as possible and it's very overlooked.

"There's a brilliant book about writing by Stephen King which opens with him saying 'nobody ever asks me about the craft'. He's not seen as a craftsman, but there's as much craft in what he does as what Will Self does. It's just less obvious. I'm really drawn to that kind of writing now. I'm editing the next book and it was already pretty tight but I'm taking out entire passages. I'm really quite brutal."

That's a cue then to do the brutal speeded-up flashback over Johnstone's 42 years on this planet. He was brought up in Arbroath, the setting of his first novel Tombstoning, the smart son of teachers. "I was basically school swot and wanted to go to uni. There was not a lot of that going on.

"I was a bit of a brainiac at most things, except art and PE. I really enjoyed physics especially and in that naive, teenage way I thought I'm going to get the answers to life, the universe and everything. We're all made of stardust, man. That sort of c***."

He came to Edinburgh to study physics. "I was good at it. I never really thought about a career. It was just getting away from home and having an experience. I was quite methodical and I found the subject interesting. I got a first and they asked me to do a PhD. It was the early 1990s, the recession. There were no jobs. They were paying me so I said yeah. And that was the beginning of the disillusionment.

"I was working on an experiment – sort of a very small-scale version of the Cern particle accelerator stuff – where you're basically sitting in a bunker analysing data for 10 hours a day as part of a team of 120 people. It got very wearing after a while. The idea of being made of stardust totally faded."

All along he was playing in bands. What was the worst name of a band he played in? "Cheesegrater. We were sort of Mudhoney meets Ned's Atomic Dustbin. And about as good as that sounds."

Perhaps unsurprisingly he needed a job after he got his PhD. He was offered work editing a physics magazine in Bristol but he'd met Trish by this point so he stayed in Edinburgh to work for Marconi. "I did a job I didn't really like for four years before I stupidly quit that high-paid job and became a music journalist."

Where there any moral qualms about the Marconi years, I wonder? This is a company who devised defence systems after all. "I never really considered it, to be honest. I was just a graduate looking to pay off a loan. The stuff I was doing – not that this is an excuse – was mainly radar surveillance for helicopters. There were people there designing rocket launchers and what have you. I did have to sign the Official Secrets Act. If only I'd had some secrets to sell. It was so boring."

In his spare time he was producing a fanzine called Get Your Crippled Ass Off My Porch and he started writing for the List. "I kinda thought, 'I could make a go of this.'" Did Trish have any concerns? "She was very enthusiastic about it. The way I see our relationship is we both back each other up. I was clearly f****** miserable in that job and we must have had a mortgage on a one-bedroom flat, but we weren't married and we didn't have kids at that point so it was relatively still easy. I started freelancing straight away."

The first novel was still some time off, but looking around him he began to think it was possible. The 1990s saw new Scottish fiction emerge in a fevered (possibly chemically induced) rush. Scotlit was suddenly hip. "To see something like Trainspotting or Morvern Callar or The Wasp Factory and recognise these people and these places and these voices they were speaking in was just an absolute revelation for me. I just couldn't get enough. Those were three touchstone books. It's interesting none of them were Glasgow books. Scottish literature up to that point seemed to me very Glasgow-centric. Alasdair Gray and all of that. And I'd never lived in Glasgow, never been a west coast person. I'd grown up in a small town, so I recognised Gordon Legge, Duncan McLean, Laura Hird. It wasn't that I didn't recognise the Glasgow voice but it wasn't speaking to me or my heart."

Johnstone's fictional Scotland is set on the margins then. Arbroath in Tombstoning, the Highlands and Islands in its follow-up The Ossians and Smokeheads and now Portobello in Gone Again (only his last book Hit and Run remains within city limits, in this case Edinburgh). That sense of place is one of the recurring motifs of Johnstone's writing. That and the inadequacies of the men in these books. "All these male characters that I write are kind of hapless," he admits. Why might that be Doug? "I don't think you need a psychiatrist's couch for that one, Teddy."

He probably wouldn't have time for an appointment anyway. Smokeheads has been optioned as a film and Hit and Run has been optioned by ITV. Before long it may be that Johnstone won't have to introduce himself as a writer any more. People will know. But what matters is not what he says he is, but what he does. "Part of me thinks I'm not writing fast enough," he tells me before we walk to Portobello beach for his close-up. "I'm writing screenplays now. I still have to do other stuff to pay bills and I still have to do the school run. But part of me thinks I could write a novel in a week."

Sounds like a challenge.

Gone Again by Doug Johnstone is published by Faber and Faber, priced £12.99.

Doug Johnstone