Something strange happened before Christmas. For an hour, Theresa May's Cabinet didn't discuss Brexit. Instead, and for the first time, they talked about mental health. No, it wasn't in preparation for the PM's visit to Washington, but because of some new and concerning research.
Despite what you might think amidst relentless reports of mental health services struggling to keep up with demand, proportions of people with mental health disorders have remained relatively stable for decades. More people are willing to talk about mental health and to seek treatment. Levels across the population, however, have remained pretty much the same. That is until now.
The Adult Psychiatric Morbidity Survey, a large review of psychiatric disorders, reported a significant rise in mental illness in young women. Over a quarter of 16-24-year-old women now experience a mental disorder, an all-time high, mostly accounted for by anxiety related disorders. This rare rise makes young women three times more likely than young men to experience mental ill health.
We don't know what has caused this rise. That doesn't stop people putting forward various theories. Social media is a key contender; a usual suspect whenever younger generations' well-being is questioned.
A few interesting memes about me float around the internet, and it's not unusual to spot steam rising from my twitter account at any hour. I'm confident though that none of this has significantly changed my mental wellbeing.
As a sixty-something on the social media block, however, my experiences with social media are almost incomparable with twenty-somethings.
Today's 16-24-year-olds are the first to grow up immersed, or drowned, in a world of social media updates. Numerous apps flood users day and night with glimpses of others' seemingly flawless lives. Marketers make the term social media a misnomer, using these channels to stalk young users with very directly targeted advertising.
Young people spending more than three hours daily on social media are twice as likely to report poor mental health than those who don't, but we don't know if this is a direct result of social media use.
"It could be that teens with mental health problems are seeking out interactions as they are feeling isolated and alone," says Dr Hugues Sampasa-Kanyinga, an author of a major study into social media and young people's mental health.
Bullying wasn't invented by an egg-shaped twitter troll. It's as old as the hills and wasn't always synonymous with smartphones. As long as humans have interacted, bullying has been a cause of anxiety. Research from my institution confirms that the psychological impact of bullying can continue well into adulthood
Pressure to look good and exhibit success had been piled on the young, especially women, well before Instagram. Links were seen between anorexia rates and the rise of glossy magazines decades ago (levels rising as the models' proportions shrunk).
Social media booms due to its amplification of users' messages. It can provide support, entertainment and social lives. Its beauty is also a curse. It creates all sorts of different ways to be cruel, directly or indirectly. Without firm guidance about posting images or stories promoting and even glorifying self-harm, this worrying content proliferates.
Offline, young people's lives have not stood still. Innumerable other changes could plausibly account for young women's rising ill health.
Last year over 40% of 18-year-olds in England went to university. This number was in single figures in my day. Debt and exam pressures that stalk students could contribute to mental ill-health, yet don't in themselves explain why women's mental health is affected more than men's, even considering increasing numbers of women taking up university places.
Parenting has changed too. 'Over-parenting', and the other extreme, 'toxic parenting' are associated with higher levels of child anxiety and depression. Again, this alone does not explain a threefold difference between the mental health of young women and men.
To add to the complicated mix, young people accessing mental health services need to navigate through a notoriously complex 'transition' between child and adult services. It has been said that "maximum weakness and discontinuity in the system occurs just when it should be at its strongest".
Frankly, we don't yet know why there has been this rise. Some will say "so what - something must be done", but to confidently and effectively respond, we need to be clear about the causes. There are too many examples where we have leapt in armed with good intentions and even a few pilot studies, and fallen flat on our face. Interventions that seemed to be 'the right thing' amounted to the opposite. Early suicide prevention interventions in schools made things worse. Psychological treatments for delinquency had lifelong negative impacts. Intervening too early for psychological trauma increased, not decreased, rates of post-traumatic stress disorder.
The Cabinet's unusual pre-Christmas behaviour is followed up this week by the first meeting of the women's mental health taskforce, convened by public health minister Nicola Blackwood MP. This taskforce, which I am pleased to be part of, will seek to understand and address this serious issue.
Unpicking this tangle of issues will be a tall order, but we must try. The causes of the serious rise we are witnessing in the mental ill-health of young women must be identified so we can then provide these young women with the best possible support.