Silence is golden – at least where men are concerned. The “strong, silent type” endures as an aspirational archetype, whether you are a man yourself, or simply someone who interacts with them. In popular fiction, the Jack Reacher action novels have sold about 100m copies. The big man’s catchphrase is, tellingly, not a phrase at all, rather, it’s an anti-phrase: “Reacher said nothing.” In film, one of the ultimate images of machismo is Arnold Schwarzenegger in The Terminator: leather jacket, motorcycle and, famously, only 17 lines of dialogue in the whole of the first film. And at the frillier end of cultural representations of men, the likes of Heathcliff in Emily Brontë’s Wuthering Heights depend more on their ability to smoulder a lady to a crisp with a glance than on their emotional articulacy.

It might work in fiction but, in reality, the “boys don’t cry” approach can be dangerous if it leads to men bottling things up or trying to shoulder their worries alone. Suicide is still the biggest killer of men under 50 in the UK, with men making up about three-quarters of deaths by suicide.

Also disturbing, in its own way, is a study referenced in a new documentary Silent Men, which found that when a group of babies were covered randomly with pink and blue blankets, the babies assigned a blue blanket were picked up or touched less than those with a pink blanket. The unconscious attitude on the part of the participating carers was that boys don’t need to be comforted as much.

“It’s such a simplified example, but it just really was quite heartbreaking,” says Silent Men director Duncan Cowles. “It just shows that, from the get go, society is going to treat you slightly differently if you’re a man or woman.”

Silent Men is Cowles’s first feature-length documentary, following a string of award-winning shorts as well as the docuseries Scary Adult Things. He’s been compared to Louis Theroux for his likable, low-key observational style and the fact that no matter how serious his subject, his films have a levity to them. Of Silent Men, he says: “I didn’t want this to be like a serious, grim mental health film, you know? That was my worry around the title, actually. I thought: ‘Silent Men, is that a bit blunt?’ The original title for the film was Scottish Silent Blokes.”

But soon the focus broadened beyond Scotland to the rest of the UK. There he met and interviewed a number of men, all of whom struggle in some way with being vulnerable. John tells Cowles about how his decision to keep a health crisis from his own family led to suicidal ideation and divorce. Ainslie had difficulties expressing his own feelings in the aftermath of having a baby. And Larry is determined to take Cowles to a retreat for a weekend, where men will be encouraged to open up.

The film took a while to complete – Cowles started making it when he was 26 and is now 34 – and in its finished form is a gently compelling mixture of interviews, scenes of Cowles’s own attempts to become more emotionally open, and soothing footage of bumblebees and flowers captured in slow motion. It plays with documentary form throughout: Cowles feels you may want a time out at the midpoint, so pauses halfway through a talking head’s sentence. It may touch on some dark topics, but it’s not a punishing watch.

That’s entirely intentional. “I don’t think enough documentaries use humour in the right way, and people shy away from it because they think [male mental health] is a serious topic. So it should be. It is something that’s serious. But it’s tough to get people to watch independent documentaries, so I really wanted to have that balance of humour with a really serious topic, which hopefully makes it a more accessible film.”

That approach is maybe where the Louis Theroux comparisons come from, though where Theroux is throwing himself into white supremacist communities and interviews with Jimmy Savile, the Cowles approach – so far – seems to be more about ambling around pubs talking to regular guys. Is that fair? “Yeah. Duncan Cowles’s Super Mundane Weekends, that could be my next pitch. Actually, someone the other day was like: ‘Oh, you should do a documentary about Louis Theroux, that’d be funny.’ I don’t know if he’d necessarily want that, though.”

Cowles’s influences aren’t limited to Theroux – he also cites documentary-maker Nick Broomfield, reality-and-fiction-blurring comic Nathan Fielder and the absurdist Swedish auteur Roy Andersson as reference points. “Although Roy Andersson’s work is fiction, I like the way he sort of exaggerates the mundane. And there’s a real bleakness. Like, it’s super-depressing at points, but also really funny.”

That dichotomy comes through nicely in Silent Men, notably in a key scene that forms part of Cowles’s journey in the film, where he tries to tell his own parents he loves them. Part of the point of his quest, which is part therapy, part road trip, is that he hopes he’ll be able to actually sit down and say “I love you” to his mum and dad. He does this while filming them, and capturing his own reaction on a different camera.

For some families, the scene is probably baffling. How is it possible that this guy has never said “I love you” to his parents? How is it possible that they’ve never said it back to him? But it will be all too relatable for huge sections of the UK, where familial love is assumed but rarely spoken aloud. In his dad’s reaction, you can see why the focus here is on men’s difficulties with articulating emotion. Cowles senior has an instinct, which comes to seem more and more like a compulsion the longer the scene plays out, to undercut the moment, to deflect, to avoid, to make jokes.

When Cowles junior finally spits it out and says he loves them, anyone who has seen any reality TV or Hollywood films will be expecting to hear the parents say it back to him. Their response is mild acceptance, but they don’t explicitly reciprocate the sentiment, and watching the moment where that beat of storytelling would usually arrive is lightly disorienting. It’s something that caused some tension for Cowles, too, who says that he intended it to play as an upbeat moment, because he fulfilled his quest and said those difficult words. He was surprised to find audiences experienced it differently, and felt sorry for him.

“I was kind of annoyed!” He laughs. “I wanted people to see it the way I did, but now I can see what they mean. You can see disappointment in my face, so I’m not really hiding it. It’s a funny one: they’re a little bit awkward, and then they go and make a cup of tea and life goes back to normal and no one talks about it again. But there’s more truth in that, I think, than what you see in reality TV and stuff. Reality’s the exact opposite of reality TV. It should not be called reality TV at all.”

This is part of why the film, modest though it is, is so resonant as a piece about mental health. It doesn’t try to say that if you’re struggling, having one conversation will be transformative. But what it does do is highlight the importance of taking the first step, and talking to someone. “There isn’t one fixed thing. It’s not: ‘Go and cry and listen to some music and then you’re sorted.’ Those sort of things might be a coping mechanism, but they’re not fixes. It’s a gradual thing of tweaking your life and trying to improve it in different ways.”

That journey will look different for different people and, as Cowles says, it isn’t about completely reinventing your personality. In the sequel, Terminator 2: Judgment Day, Arnie is no longer a taciturn killing machine. He’s still a killing machine, but he’s a kinder, more communicative one. He’s been reprogrammed and begun to learn about human emotion. As he puts it: “I know now why you cry.” Slowly but surely, perhaps silent men, or some of them anyway, are on a similar trajectory.

• Silent Men is in cinemas from 19 November for International Men’s Day.

In the UK and Ireland, Samaritans can be contacted on freephone 116 123, or email jo@samaritans.org or jo@samaritans.ie In the US, you can call or text the National Suicide Prevention Lifeline on 988, chat on 988lifeline.org, or text HOME to 741741 to connect with a crisis counselor. In Australia, the crisis support service Lifeline is 13 11 14. Other international helplines can be found at befrienders.org