I CAN pinpoint the first time I watched a horror film to the very day and hour.

The movie was The Masque of the Red Death – Roger Corman's wonderfully lurid reinterpretation of Edgar Allan Poe's classic story of evil and power. I was about two-and-a-half-years old. I remember creeping downstairs for a drink of water, the house all dark and warm and drowsy. It seemed like the dead of night. I peeked through a crack in the door. The adults sat around the TV, and I watched them watching what was happening on screen. Even then I had the necessary voyeurism that all true horror fans need.

The scene unfolding on the screen still thrills me whenever I see it: a man has come to a masked ball dressed in a gorilla suit (good horror always needs a sense of the darkest comedy and wicked absurdity). A vicious little dwarf takes a candelabra and sets the suit alight, the man inside burns to death, screaming in agony as the revellers first laugh, thinking it a joke, and then scream and run in panic. This was some horrible entrancing magic I was seeing in front of my little toddler eyes. Instead of shrieking like a stuck pig and racing into my mummy's lap – like any normal child would do – I crept quietly into the room and sat silently on the floor watching the rest of the film; my parents only realising I was there when God Save the Queen started to play on TV, telling 1970s Britain it was time to go to bed.

I can work out the time that the film was on telly as the movie played as part of the Saturday night horror double-bill that ran on BBC2 back then: it was about half eleven, by my reckoning. Aficionados will remember that the horror double bill usually kicked off with a classic black-and-white Universal or RKO picture such as The Wolfman or The Mummy, before serving up a more severe dish of modern technicolor mayhem from Hammer or American International Pictures. And I know I was two-and-a-half, as my mum tells me she remembers the date very vividly. The day before was Bloody Friday.

I'm from Northern Ireland and we have a lot of days branded bloody back home. But Bloody Friday was particularly horrific: 22 IRA bombs exploded across Belfast in just a matter of minutes. Nine people died, 130 were injured and the TV news images that ingrained themselves into the minds and souls of the people of Ireland were those of blackened lumps of human flesh, arms and legs, being shovelled off the streets by firemen and placed in black bin liners. True horror: humans as garbage. Of course, I would have seen the images on TV of the aftermath of Bloody Friday back then – every child in Ireland would have. But I've chosen to remember the fantasy of violence rather than the real violence. That's probably a good thing. Self-preservative, maybe.

Horror has always been the pervert at the party when it comes to cinema, art and literature. The crazy cousin from the backwoods who walks with a limp, drools when he eats, and is too friendly with his sister. However, this weekend horror is about to come creeping shamefully into the spotlight – as it does every two years or so when a fad such as beautiful, shiny-skinned teen vampires reaches critical mass – thanks to World War Z, and that kind of makes me a bit sad but kind of happy too. Folk who usually sneer at horror movies will queue up with their kids – it's a certificate 15 – to watch what is in effect just a classic summer blockbuster. Zombies are so hip these days that everyone just has to go to see it. In fact, zombies are about as much where horror movies are at right now, as Mumford & Sons are at the cutting edge of modern British folk music. Nevertheless, Brad Pitt's popcorn vehicle will give the genre a little lift, and money might start trickling down through the studios until it reaches movie-makers who want to do something new with the art form. I have to confess though, Z has a kernel of old-school horror at its heart, and some great scenes – the transformation of Glasgow into Philadelphia is astonishing, and who doesn't get off on a wall of the Living Dead?

We've been here before. The horror-blockbuster summer cross-over is nothing new. Cinema is predictably cyclical. Remember Jaws? An old-fashioned creature feature. Silence Of The Lambs? A thriller pretending to be a horror film. And, of course, the mainstream blockbuster that was the first big populist fillip for the genre since the mass-appeal classics of the 1930s: Psycho. For a hardcore horror fan like me, it is a weird sensation walking into a full cinema. When Henry: Portrait of a Serial Killer came out in the early 1990s, I was the only member of the audience in the art house cinema in Belfast I frequented. By the time I'd watched the film a third time – alone in the stalls each occasion – even my weirdo friends who worked as usherettes were starting to think there was something a little wrong with me.

I can be a bit old-fashioned when it comes to theories of art and literature. Sorry to sound poncey, but I was taught Aristotle's theory of poetics at my grammar school and university. Lesson 101 of the poetics is catharsis: how art can purge our worst feelings from us and make us better people. We watch tragedy to purge us of feelings of pain and sorrow, and horror to purge us of feelings of fear and dread. Now think of the great tragedies: Oedipus Rex, Antigone, The Jew of Malta, Doctor Faustus, Macbeth, King Lear, Titus Andronicus. Those plays contain moments so ghastly they might well have ended up on the Video Nasty list if they'd been made in the 1980s. Eyes torn out, madness, fathers murdered, children butchered, devil worship, mass poisonings, sacrifice, rape, mutilation, cannibalism and enough executions to keep Tyburn Tree fully occupied for months.

Good horror – and I stress good – and tragedy are often one and the same. For me great horror doesn't depend on zombies, werewolves, vampires or ghosts: real horror depends on what human beings, real people, are doing to other real human beings. Let's forget World War Z for a second, as it is blockbuster cinema, no more no less, and let's look at the Draculas, Werewolves, Frankensteins, Exorcists, Living Deads. To horror geeks like me these are spook shows, ghost stories, monster movies, survival thrillers. I still love them as they are exhilarating and make me jump – the current Channel Four undead series The Returned is a chilling gem – but real horror is just people, and isn't that a truth which we can all universally hold: hell is other people.

So what is real horror? I once went to a horror film festival to see Funny Games – an art house movie by the acclaimed Austrian director Michael Haneke. To me, it's the greatest horror film ever made. The audience was warned: "If you can watch this film to the end, without looking away or leaving the auditorium, then you have to ask some big questions about who you really are as a human being." For a horror movie freak, this was a challenge I couldn't resist, and one I failed. About halfway through – and if you've seen it, you'll know the part I am talking about – I had to get up and leave the cinema for a few minutes. Funny Games is a simple study of what human beings can do to other human beings. There is very little blood on screen: one splatter against a wall and a bloodstain on a character's trousers, that's all. You'll see more blood in EastEnders. But the film drives relentlessly at unravelling what makes humans cruel, what a human can withstand, the limits of love and suffering. However, torture porn, like Hostel, it is not.

Bubbling away, far from the eyes of fans of World War Z, there is a growing number of films influenced by Funny Games: self-consciously artistic, well acted, well scripted, well directed. The best come from the French horror new wave, movies like Frontieres, Switchblade Romance, Inside, The Ordeal and Martyrs. My wife, like most people, isn't a horror movie fan – and self-evidently, therefore, she is looking forward to seeing World War Z. But let me tell you about the time I tricked her into watching Martyrs. I told her the truth – in stunted form – saying it was a dark French art house movie. That tickled her. What I didn't say was that it is a dark French art house movie that deliberately sets out to destroy the viewer just as it destroys its lead characters. My wife, who loves me very much, I think, flew into such a rage of disgust and revulsion at what I'd made her watch that she swore, shouted, threw cushions about and stormed off to bed. It took a full day for her to forgive me. Case closed, I think, when it comes to expressing the power of horror.

Britain punches way above its weight when it comes to creating these small, sparkly dark gems that glow in our art houses but are lost to the popular imagination. I challenge anyone to watch Eden Lake – featuring Michael Fassbender in one of his earliest roles – and at the end not be left twitching in shock. The film is a beautiful awful study of feral Britain. When art and horror work well together, they are best friends. A film like Eden Lake strikes right into the fearful soul of the viewer, society and culture. That other great recent British horror film, Kill List, a bizarre curdled cocktail of The Wickerman, The Devil Rides Out and Get Carter could have been penned by Pinter with Beckett as script adviser.

Many great horror films, unlike Kill List or Funny Games, don't wear their artistic credentials on their sleeve. Most punters think The Texas Chainsaw Massacre does exactly what it says on the tin – that it is all kill, kill, kill. Well, there is plenty of killing, for sure, but, like many of the great horror exploitation movies of the 1970s, it operates on a much deeper level than a slasher film. When I was a teenager in the 1980s – before the folk in government who didn't watch movies or listen to music decided to ban everything they could with the Video Nasty List that outlawed films like Driller Killer, Nightmares in a Damaged Brain and Cannibal Ferox (all half-decent films, by the way, if a little demented) – I would toddle down to the local video library when my mum and dad were out on a Saturday afternoon, and me and my mates would hire out the likes of Texas ... or Last House on the Left – the law was louche in those days – and sneak them home where we could watch them until the adults came back. Let me tell you, at a time and place which saw mass murder on the streets of my cruel wee country, those hours spent with my mates cowering from make-believe horror somehow made life more liveable. Clearly, then, I'm not the type who believes that books, songs or films turn people into murderers. It's partly the environment in which a child is raised that forms them into killers, but mostly it's the parents and family that fate deals a child that misshapes them morally and psychologically. At least that's what 20 years as a crime reporter has taught me.

My first novel, All the Little Guns Went Bang Bang Bang, has just been published. These days, it's what they call literary fiction. It's not crime or thriller – at its heart it's a love story which comes with a hefty dollop of the horrific, offset by the darkest comedy I could construct. It tells the story of two 11-year-olds back in Northern Ireland in the early 1980s: a boy named Pearse Furlong and a girl named May-Belle Mullholland. Screwed up and damaged by the world around them – their cruel, brutal parents, and the ugliness of the society they live in – they take to the streets of Troubles Ulster like a pre-teen Bonnie and Clyde, guns in hand, deciding to level the score against the world around them. Some readers have been horrified by the violence both inflicted on the children and that the children inflict on others. In those scenes of violence, of course I was trying to horrify, because art is horror, if art really examines a true life, for what life hasn't been touched by horror and aren't those moments of horror the moments that make us most alive – that define a life. When we live in a world that is both terrified of our children and terrified on behalf of our children – Britain is after all both post-Bulger and post-Dunblane – I thought that a catharsis of shock, pity, fear and dread might do you all some horrible good.

l Neil Mackay is the Sunday Herald's news editor. His debut novel All The Little Guns Went Bang Bang Bang is out now, priced £8.99 from Freight Publishing. Poet and novelist John Burnside, winner of the TS Elliot Prize and Foward Prize, calls the book "a powerful, dark novel that is both compelling and necessary". Janice Forsyth, of BBC Radio Scotland's Culture Studio, said: "I couldn't put the book down. I read it from start to finish in one go. There's this extraordinary balancing act of brutality and lightness of touch where we really believe in these little children with their innocent souls, we're really rooting for them. Exquisitely written." The Irish News said it was a "heart-rending study on human unravelling ... the voice of a child is used to searing effect". The Skinny called it "a splendid debut ... Mackay's skillful writing, grounding the pair in authentic family histories, makes Pearse and May-Belle rounded souls despite the terrible things they do". The Sunday Herald's sister paper, The Herald, said the novel was "powerfully written ... Violence spatters the book ... a splendidly compelling debut".