Hospital admissions for eating disorders have risen 37% across all age groups in the last two years, NHS Digital figures show.

Psychiatrists and experts in eating disorders say the figures are worrying and show that more needs to be done to support people before they reach crisis point.

Admissions rose from nearly 14,000 in 2016-17 to 16,000 the following year and 19,000 in 2018-19.

A quarter of the admissions in 2019 were children aged 18 and under, with 2,403 of those for anorexia, up 12% from the previous year. This included 10 cases of anorexia among boys and six among girls aged nine and under. The most common age for patients with anorexia was between 13 and 15.

Dr Agnes Ayton, of the faculty of eating disorders at the Royal College of Psychiatrists (RCP), said the rise was a concerning sign that problem was not being treated properly in its early stages.

“Rising hospital admissions for eating disorders are very worrying as they are the deadliest mental health disorders. Patients often face long delays in accessing specialist treatment. The government must ensure eating disorder services are properly staffed to help bring waiting times down and reduce the need for hospitalisation,” Ayton said.

It is unclear to what extent the rise may reflect increasing awareness of the disorder, but Ayton told the Guardian it was probable more people were becoming ill.

“The threshold of admissions to hospital is high, it happens when the situation is life-threatening, [so] that does suggest that more people are becoming severely ill,” she said. “The causes are complex, and much more research needs to be done in the light of these findings. Anecdotally, reasons could include increasing pressures on children in schools, and advertisements encouraging unrealistic ideas of body image.

“Hospitalisation is the tip of the iceberg. We know that with both children and adults people sometimes aren’t seeking help early enough so they get to a critical state when it’s not safe to manage their treatment in the community, so we want to encourage people to seek help early.”

Ayton and her colleagues at the RCP are calling for more investment in specialist psychiatrists to help tackle the issue. The rate of unfilled NHS consultant psychiatrist posts in England has doubled in the last six years, with one in 10 posts now vacant.

“One in six eating disorders psychiatrist posts are unfilled,” Ayton said. “The majority of patients are first seen by non-specialists with as little as two hours’ training. We really need more specialist psychiatrists.”

The NHS data echoes other evidence that cases of eating disorders are rising. Last year, a study from King’s College London suggested that rates of anorexia among pre-teen children in the UK and Ireland had doubled in 10 years.

The study, which looked at cases of anorexia diagnosed by psychiatrists in hospitals or specialist clinics, estimated that 3.2 per 100,000 children aged between eight and 12 met criteria for anorexia for the first time in 2015, compared with 1.5 to 2.1 per 100,000 in 2006.

Emma Thomas, the chief executive of the charity Young Minds, said “While there have been some improvements in community care for young people with eating disorders in recent years, it can still be difficult for children and young people to get the help they need before they reach crisis point. Getting early support for an eating disorder can prevent problems from escalating, meaning young people are more likely to fully recover.”