AS the daughter of Iranians who fled to the US just before the revolution, former Time Magazine journalist Azadeh Moaveni was taught from an early age to distrust mainstream narratives about the west.

"I was raised in a community that felt itself very much impacted by American foreign policy," she explains. "Young people growing up in the US very often come from places with a history of colonialism so there was that kind of inherited scepticism of the conventional understanding about who is to blame, who is the enemy, along with all of the identity challenges around being an Iranian woman in the US: feeling torn, feeling it was not possible to be properly American while being Iranian or Muslim; navigating all these identities that seemed to be at war.”

Moaveni had already explored these tensions in a memoir, Lipstick Jihad, where she described early fantasies of herself as a Persian princess and explored the "distorting myths of exile." Years later, while living in London, she was less baffled than most by the behaviour of young British Muslim girls like Glasgow's Aqsa Mahmood and the four teenagers from Bethnal Green who began leaving their homes to join ISIS in Syria and Iraq.

"I was still shocked," she tells me. "For a start, a lot of the girls were from south Asian backgrounds – they weren't Arabs. And we hadn't seen a march of people going to Palestine, Afghanistan or other theatres of Muslim suffering.

"But the contours of it felt familiar to me: who these girls were – their vulnerabilities, scepticisms, resentments – all that seemed very intimate. It was intelligible to me how these things had been used against them."

Moaveni's emotional connection – rare in the portrayal of young female defectors – echoes throughout her forensic yet empathetic new book, Guest House for Young Widows: Among the Women of ISIS.

Having won the confidence of a handful of those seduced by ISIS propaganda, she delves into the susceptibilities of those who answered the call and the hypocrisies of a government that turned its back on its own citizens. Always nuanced, she tears up the caricature of psychopaths unfazed by beheadings, and paints a more comprehensible portrait of culturally dislocated girls won over by recruiters who knew exactly which buttons to press.

The women we follow come from the UK, Germany, Tunisia and Syria and diverse personal circumstances. There is Lina, a victim of an abusive relationship, in search of a happier second marriage; Emma/Dunya, a Muslim convert who hopes to escape a hostile mother-in-law, sisters Rahma and Ghoufran who fall under the spell of Salafi activists, and Sharmeena, Kadiza, Amira and Shamima (Begum), the 15 and 16 year-old school-girls who attracted worldwide opprobrium when they ran away from their homes in Bethnal Green, London.

Moaveni first wrote about female defectors in a Pulitzer-prize shortlisted piece for the New York Times in 2015. Gaining the co-operation of enough girls to write a book, however, was a protracted process.

"In countries with an effective counter-terrorism apparatus, like the UK, it was particularly tough because people knew they were being watched and were reticent," she says. "It involved going through layers of outer rings of people's lives, cultivating the trust of an increasingly shrinking circle of people to reach the inner ring."

Despite identifying with the girls, Moaveni had her own prejudices to overcome. From a secular background, she found it difficult, at first, to understand "the pull and draw" of religion. And then there was the question of whether or not her interviewees were credible. Early on, she failed to pursue the story of a graphics arts student in Tunisia because it seemed outlandish to her that this girl with a pixie haircut and tattoos might have spent a year with ISIS. Later, she realised it was perfectly plausible. There was, she discovered, no "typical" background for a defector; ISIS recruiters were able to net privately-educated middle class girls almost as easily as working class girls.

If there was a common theme, it was a sense of alienation. "A lot of these young women felt excluded, maybe at the scale of their neighbourhood, but also on a national level where they were being castigated in the press and forced to endure an intense level of public racism."

Mahmood's defection to Syria in late 2013 had a dramatic impact in Scotland, which had no history of Islamic radicalisation. At 19, she was far from the youngest to make the trip, but she was one of the first and from an affluent and educated family.

Mahmood, who became known as Umm Layth and is believed to have died, became a key propagandist for ISIS, using blogs to recruit others. These blogs were remarkable for their blend of western text-speak and fundamentalist ideology.

"Aqsa was fascinating; she was a classic example of cult-grooming because she lived so entirely in this interior life," says Moaveni. "She seemed to me to be one of those teenagers who had decided to be extremely idealistic about something; she chose this cause, but it could just as easily have been climate activism.

"And she used all the tools of her western upbringing to marshal that idealism, so she became this hybrid phenomenon, sharing her experiences in an individualistic, millennial way.”

Moaveni agrees the Glasgow teenager's endorsement of violence was chilling. “And yet, you can see why a naïve, morally inexperienced Muslim woman might be drawn to the narrative that 'we endure this great violence, so why are you surprised when we then inflict it back?' It's extraordinarily crude and limited but from the narrow perspective of a teenager it could make sense."

Guest House for Young Widows encourages the western, non-Muslim reader to see the world from a Muslim perspective. In one key section, Moaveni describes what has become known, in policy circles, as the "al-Qaeda narrative". It states that “the west invades Muslim countries, cultivates and backs corrupt dictators who subvert the will of the people and overthrows popular leaders it deems hostile to its interest. In response, political violence in places like Palestine and Iraq is an acceptable form of self-defences against occupation." The problem, Moaveni says, is that “to many Muslims this doesn't sound like the 'al-Qaeda narrative', it sounds like their lived reality”.

The journalist also riffs on psychoanalyst DW Winnicott's concept of the "good enough" mother – one who steadily allows her child to experience enough frustration to develop in harmony with the real world – to come up with the "good enough” Muslim household. In such a household, she writes, "children are instilled with an intense, deeply felt concern and responsibility for the plight of Muslims everywhere, but made to understand that they must also bear this reality without resorting to indiscriminate violence".

She goes on: "It was not so much, then, that [defectors] were brainwashed into an ideology of radicalism; they simply lacked the intellectual and psychological coping skills to channel their newly-found beliefs into more productive and legal means."

Guest House for Young Widows follows the girls' experiences and gradual disillusionment as a succession of husbands become martyrs and ISIS falls. Some of them make it home; some die, many are still in refugee camps.

In the US, the policy is to repatriate female defectors and their children; but here in the UK, we would see them die before we would let them back into their home country. This political abdication of responsibility was laid bare when, having lost two babies in Al-Hawl camp, Begum begged to be allowed to bring the third home to safety. Not only was she refused, but Muslim Home Secretary Sajid Javid stripped her of her citizenship.

"The government's refusal to bring back these women and their children from the camps is a singularly political decision," Moaveni says. "It seems such an unnecessary price to pay because ultimately we are talking about a very small number of very vulnerable people.”

It's racist, too. When white 15-year-olds are preyed upon by sex offenders, we have no problem accepting they have been groomed. Yet Muslim girls lured away to become ISIS brides are held responsible for their violation.

“This is supposedly the age of evolving and mature feminism and yet it became absolutely clear to me that white British feminism was an exclusionary, racist, extraordinarily limited project because people were writing about these girls packing lubricant and going off to be 'whores' for ISIS,” Moaveni says. “These were middle-class women writing about brown 15-year-olds. If those girls had been white, they would not have done it."

Many of these demonised young defectors are languishing in terrible conditions. According to the International Rescue Committee, 171 children have died in Al-Hawl since Begum's son, Jarrah, in March. In future years, will she be seen as the ultimate symbol of callous times? "That's a good way of putting it," Moaveni says. "If she had been a white woman who went to Egypt with a suitcase full of opioids, there would be a mass mobilisation to get her out of some dank prison. Yet, in Syrian camps, British children are being allowed to die. It's a massive indictment of the deeply populist and dark moment we are living through."

Guest House For Young Widows: Among the Women of ISIS, by Azadeh Moaveni, is out now on Scribe, priced £16.99.