Rahaf, aged 10, from west Mosul in Iraq, can’t tell you what caused the war that left her an orphan, killed her friends and robbed her of her childhood. But she can give you a child’s-eye view of the collective trauma, grief and loss that weigh on children across her devastated city. “I wake up and I witness war every day. I don’t want to go through another war,” she says.

One year after Mosul was retaken from Islamic State by Iraqi-led forces, work has started on reconstruction. Yet for children trying to rebuild their lives, cope with loss and keep alive the hope on which the future of their city depends, the response so far has been derisory.

While aid agencies and the Iraqi government focus on rebuilding cities flattened by war, the psycho-social needs of thousands of children who suffered traumatic experiences are being sidelined.

“Flattened” doesn’t do justice to west Mosul. Crossing the old iron bridge across the Tigris into west Mosul is like entering a scene from Stalingrad or Dresden. This is where Isis fighters made their last stand. Entire districts were reduced to rubble by the explosive weapons delivered by US-led coalition airstrikes and Iraqi artillery. The nine-month assault was described by US officials as the most intense urban fighting since the second world war.

Looking at the piles of stone and twisted girders that were once homes provides a glimpse of the terror experienced by civilians trapped by urban warfare. It is impossible to know how many were killed or wounded by snipers and car bombs. What is clear is that many children emerged from the military devastation, and the three years of Isis rule that preceded it, carrying deep psychological scars.

At the sprawling Hamam al-Alil camp for displaced people who fled west Mosul I meet Ayesha, 12. She saw her mother killed by a shrapnel blast that left a chunk of metal in her own chest. Ayesha is being cared for by an aunt who lost her own daughter, two brothers and her father. The aunt breaks down in tears as she describes her struggle to cope.

Like most of the 300,000 children from west Mosul still living in displacement camps, Ayesha is not going to school – denying her a chance to restore some sense of normality.

Back in Mosul, 13-year-old Dina, like most of her friends, dropped out of school for the three years of Isis rule. “I didn’t want to learn about killing westerners and suicide bombs,” she says. Eventually Dina and her family escaped Mosul. But not before she had seen the aftermath of a coalition airstrike that left more than 20 dismembered bodies strewn across a street. She still has nightmares.

You can’t quantify the impact of such traumatic experiences, but in a new survey from Save the Children almost half the children reported feeling grief either always or most of the time. Only 9% of those interviewed reported being able to think of a source of happiness in their lives. Only 25% of adolescents considered school a safe place – unsurprisingly given that most of the city’s schools were destroyed.

One of the most alarming findings was the degree to which children are struggling to cope. Most children reported feeling unable to talk to their carers about their distress, in part because they know their parents or relatives are not coping. “These children are at serious risk of further and long-lasting mental health issues,” says Yousra Semmache, one of the report’s authors.

All of which raises some fundamental questions about how we think about reconstruction. Last February, at a conference in Kuwait, aid donors pledged $30bn in aid, credit and loan guarantees for rebuilding Mosul and other cities. Almost the entire amount is linked to the reconstruction of roads and buildings. Nothing of substance was pledged for what is arguably the greatest reconstruction challenge of all: helping children traumatised by war cope with their experiences and rebuild their lives.

Humanitarian agencies have delivered life-saving aid, shelter, health and education. Yet here too psycho-social support figures as a footnote, accounting for around $1m in aid delivered in 2017. There are currently no assessments of psycho-social support needs. To make matters worse, humanitarian aid for this is fragmented, short-term and unpredictable.

To its credit, the Iraqi government recognises the scale of the problem, but as in other areas delivery is dogged by institutional capacity.

So what needs to happen? Humanitarian agencies – including Save the Children – should be working together to conduct structured psycho-social assessments in places like west Mosul and other war zones. Quantifying the problem is a first step to estimating the financial and institutional requirements for tackling it – and agencies such as Unicef and the World Bank could lead in this area, working with government ministries.

Of course, aid alone will never be sufficient to tackle the crisis facing Iraq’s children. But a reliable flow of aid could help finance trained care workers, teachers and support systems and be delivered through schools, early learning centres and home care. Allocating just 0.5% of the $30bn pledged for Iraq to pyscho-social support and education would provide $150m – and it’s hard to think of a better investment.

Rahaf’s story is a tragic microcosm of what is happening to children in conflicts from Iraq and Syria to Yemen and Myanmar. We can’t remove the psychological scars these children will carry for the rest of their lives. But we can start to recognise that there is more to postwar recovery than restoring bridges, roads and buildings.

• Kevin Watkins is chief executive of Save the Children UK