Ross Hunt, his wife and their new baby were still on the maternity ward when he knew that something was wrong. “I realised I didn’t really want to hold her,” he says. The nurses handled her so casually, so instinctively; their ease made him recoil. “They lifted her up, blanket around her. I thought: ‘She’s tiny. I don’t want to touch her.’ But they made me.”

Back home, Hunt’s estrangement began to bed down. There was “just no connection” between him and the baby. His wife would dress little Isabelle, “looking all cute. She’d show me – and there was just nothing there. I’d wanted a baby so much; I assumed that when I had one, I would be fine. But any time Isabelle came to me and started crying, I almost took it personally.” He told his wife: “I know I don’t like her – but it’s mutual.”

There were times when he hated Isabelle; to confront any future alienation his daughter may feel discovering this, he has written an open letter to her on his parenting blog, to read with her when she is old enough. “I’m hoping she will understand eventually and see that I do love her,” he says.

Hunt, 26, from Newport in Wales, had experienced depression before, so he understood that he was “back in a bad loop”. He was still unprepared, though, when his doctor told him: “This sounds like postnatal depression.” He had read lots of parenting books during the pregnancy. The subject of paternal postnatal depression had scarcely surfaced and he had understood it only as something that might be triggered by a postnatally depressed partner.

This is not surprising. Largely, postnatal depression goes undiagnosed in men – aided, no doubt, by the popular misconception that it is caused by the hormone changes a mother experiences after giving birth. “That’s wrong,” says Andrew Mayers, a psychologist specialising in perinatal mental health at Bournemouth University. First, there is some evidence that men’s testosterone levels drop when they become fathers. Second, he says, “postnatal depression isn’t just hormonal. It’s about a whole series of factors in each individual’s psychology or history that kick in on top of everything else.”

In 2016, a meta-analysis of research found that 8% of men experience postnatal depression. But academics last year found that the screening tools for detecting it in women (the Edinburgh scale) are less reliable when applied to men, suggesting that the real figure is much higher. Elia Psouni of Lund University in Sweden, who led that research, says that 22% of male respondents in the study had experienced postnatal depression. With health services reaching so few fathers with depression, her research team went to “sports centres and car and motorbike forums” to recruit participants. In the UK, a National Childbirth Trust (NCT) survey of new parents in 2015 found that about one in three fathers said they were concerned about their mental health.

Mark Williams … ‘I’m from a mining community. We never talked about mental health.’ Photograph: Gareth Phillips/The Guardian

Yet postnatal depression in fathers still lacks recognition. In the UK, the National Institute for Health and Care Excellence (Nice), which guides clinicians and NHS commissioners on treatment, sees postnatal depression as explicitly maternal. The World Health Organization (WHO) also recommends screening for women only. (Type “paternal mental health” into the WHO search bar and it replies:[itals] “Did you mean: maternal mental health?”) To some, the phrase “paternal postnatal depression” still carries a faint ring of provocation. When Hunt wrote about his experience for the mental health charity Mind’s website, for instance, he says: “They didn’t want to use the phrase ‘postnatal depression’. They just wanted to call it ‘depression as a dad’.”

Now, a growing body of research is challenging such attitudes. A petition, led by the Fathers Reaching Out group, which campaigns for more understanding of fathers’ mental health issues, is asking Nice to change its guidelines. But how does paternal postnatal depression manifest itself in men – and can recognising it as a disorder change our understanding of the maternal experience, too?

“A dad with postnatal depression comes across as a bad dad,” says Mark Williams, 44, a father of one from Bridgend Valleys, who founded Fathers Reaching Out. “He doesn’t want to change a nappy and be involved.” Williams didn’t really believe in depression – of any kind – when he became a father: “I’m from a mining community. We never talked about mental health. I was one of those people who would say: ‘Depression? There’s always someone worse off!’”

Williams became a father nearly 14 years ago. He and his wife had good jobs; he was a sales and marketing trainer and she worked for British Gas. The pregnancy was planned. But a difficult labour led to an emergency C-section, and the memory of that still resurfaces. “It was like: ‘Oh my gosh! All these knives …’” Williams had the first panic attack of his life right there in the hospital.

Photograph: Getty Images

Within days of returning home, his wife, Michelle, began to suffer with severe postnatal depression, to such an extent that they now believe she should have been admitted to a secure mother-and-baby unit. Concerns about her health – which in turn reawakened the fear for her life that he had felt during the birth – became overlaid on Williams’ own feelings of insufficiency. “The fact that my wife had postnatal depression, the worry that I wasn’t going to be good enough to be a father, [concern about] how I was going to support this child, waking up with nightmares about the birth …” he begins. “I just didn’t get this overwhelming feeling of love for the baby.”

Williams began to catch himself behaving out of character. He was “frustrated, drinking and worried for my situation, trying to avoid myself, family and friends”. He had always been “a very smiley person”. Now he became angry.

Williams believes that although some symptoms – including feelings of unworthiness, sadness, anxiety, a prolonged lowering of mood and lethargy – are common in mothers and fathers, postnatal depression “looks different in men”. In what way? “There’s more avoidance, overworking, drinking and substance abuse,” he says. “I was drinking. I got into fights with bouncers. I had my personality totally change.”

Williams’ experience chimes with that of Russell Shedd, 40, a teacher and performing artist from San Diego in California, who is receiving therapy for postnatal depression 11 months after the birth of his daughter. “Anger was definitely one of the things I experienced. Frustration, irritability. Absolutely,” he says. Postnatal depression was mentioned only fleetingly in his antenatal classes: “It passed through the back of my mind.” According to Psouni, these sorts of reactions, “the angry, the nervous, the distracting oneself with work or sport, do not really figure in conventional approaches to depression. Not including these things when we are assessing depression probably means we are missing more men than women.”

It is this lack of awareness that is driving Williams to petition for fathers to be routinely screened for postnatal depression through the Fathers Reaching Out #Howareyoudad campaign. “I was finding all these men who were going through relationships ending [and using] drink and drugs,” he says. “No one was asking Dad how he felt about his mental health.”

Williams himself was never diagnosed with postnatal depression. He kept his depression to himself until, six years after his son was born, other illness in the family triggered a breakdown. He was also diagnosed with attention deficit hyperactivity disorder (ADHD).

Photograph: Alamy

Williams is clear that his wife’s postnatal depression was a contributing factor in his own decline. But paternal depression does not always work this way. Hunt, who is working on this week’s postnatal depression awareness week with the antenatal and postnatal support service Pandas, recounts how his wife, Rachel, “used to sit there Googling: ‘Bonding with dad’. She’d try to take over the bad bits and let me have the good moments.” She had no depression herself. “It was really hard for her. She didn’t know what to do.”

The interplay between fathers and mothers and the propensity of each for depression is complex. Research has shown, for instance, that men who have a better relationship with their partner and who bond with their newborn child have a larger drop in testosterone levels than those who don’t. “They may be at more risk of depression themselves, while lowering their partner’s risk,” Psouni says. Would a better grasp of postnatal depression in men improve our understanding of how it affects women? “Absolutely,” says Sarah McMullen, the head of knowledge at the NCT.

It can feel taboo, she says, for women and men to admit the scale of personal disorder that a baby can bring. “There’s the strain on relationships, sleep deprivation, changes in financial stability, the impact of birth experiences … People can feel very, very isolated. It’s a really difficult time in different ways for everyone.” The focus on men’s postnatal health, McMullen believes, “is helping to widen the conversation for women”.

Williams says his experience “totally put me off having another child”. Shedd always thought he would only have one. Hunt and his wife, meanwhile, are trying for a second baby. He acquired awareness of postnatal depression the hard way. But, he says: “If there’s a next time, I’ll think: ‘That’s OK. It was the same with Isabelle – and I came through.’”

For help with the issues raised in this article, contact Fathers Reaching Out: reachingoutpmh.co.uk