In 2017 there has been report after report of a growing gender divide in mental health, with rising rates of mental illness among girls and young women. There has been little action to tackle these. In 2018, we have an opportunity to get things right.

From the intervention of a senior judge in the case of Girl X to rising numbers of girls and young women undergoing mental health admissions, self harm and suicidal thoughts, there has been wide range of evidence over the last year showing that our girls are facing a mental health crisis.

The reasons given by commentators for the worrying deterioration in young women and girls’ mental health tend to be the same: pressures of social media, body image and school. These things are undoubtedly part of the picture. But they are not the full story.

What is especially shocking is the prevalence of PTSD, which one in seven young women experience

One of the biggest issues of the year has been the spotlight shone on sexual violence, harassment and abuse – from Harvey Weinstein and Westminster to the grooming gangs targeting vulnerable girls. This is an issue that is not going away.

For young women, the risks are particularly marked. They are facing sexual pressures, including from the availability of porn, which is informing relationships and driving the way men and boys behave towards girls and women. Sexual harassment and assaults in schools have increased in recent years. Sexual abuse and exploitation of girls remains widespread and young women are the most at-risk group for domestic abuse.

When you look at the types of mental health problems young women face, the more common disorders such as depression and anxiety are, as you might expect, widespread. But what is perhaps especially shocking is the prevalence of post-traumatic stress disorder, which one in seven young women experience. Far from this being a condition solely affecting veterans returning from wars, young women are being traumatised by sexual and physical violence and abuse on the streets, in our schools and in their homes.

The links between mental health issues and violence are well-established. Research for Agenda has found that out of all women who face a mental health problem, more than half have been abused. For one in four, that started in childhood.

At the same time, 2017 has seen a further increase in poverty, something that disproportionately affects women and children and which is another risk factor for poor mental health. There can be a tendency for commentators to look at mental health from a middle-class perspective, and to focus on social media, body image pressure and exam stress as causes. But we know that the links between poor mental health and poverty are marked.

We need to better understand and respond to these links. We need to help young women now, not store up problems for the future. Unresolved trauma and the stresses and pressure of poverty underpin many mental health issues. For some girls, their way of coping is to self-harm. For others, it is using drugs and alcohol – sometimes, it is both. This can lead to more problems such as addiction and homelessness, leaving women even more vulnerable to exploitation and enduring poverty.

To avoid this, we need to make sure help is available earlier. We urgently need to invest in mental health support in schools and communities that takes into account the particular needs of girls and young women, and identifies and supports those with experiences of abuse and trauma.

The government recently published a green paper on how to help children and young people with their mental health. Any real analysis of gender disparities was, however, lacking. But it is not too late, as these plans are currently out for consultation. 2018 is a chance to get them right.

Next year there will also be a review of the Mental Health Act, legislation on the use of restraint (something which again disproportionately affects girls and young women), and a domestic violence bill offering an historic opportunity to improve the response of public services to abuse.

I am also delighted to be co-chairing, alongside junior health minister Jackie Doyle-Price, the Women’s Mental Health Taskforce. This brings together experts on women’s mental health and involves key national organisations responsible for policy, commissioning and delivery of services, including NHS England and Public Health England. This is an opportunity to address and reverse the rising tide of mental ill health among young women.

Above all, in 2018, we must not ignore this alarming crisis, and acknowledge that gender inequality is a key driver. We need to recognise the impact of violence, abuse and poverty on young women and girls, and act now to prevent it having a devastating impact on their lives.

• Katherine Sack-Jones is director of Agenda, an alliance of 50 charities working to help women and girls at risk