There were more detentions made under the Mental Health Act in Cornwall and the Isles of Scilly last year, new figures show.
Under the act, people with a mental disorder may be formally detained in hospital, or "sectioned", in the interests of their own health or safety, or for the protection of other people.
Mental health charity Mind said legislation around mental health must be brought into the 21st century to address the "overuse of restrictive, forceful practices".
Recent NHS figures show an estimated 435 detentions were made in the year to March within the NHS Cornwall and the Isles of Scilly Integrated Care Board area – up from 370 the year before.
Across England, 52,460 new detentions were recorded last year, up from 51,310 in 2022-23.
Nationally, black people continued to face a higher rate of detentions under the act – over three times the rate of white people.
Minesh Patel, associate director of policy and campaigns at Mind, said the figures will "bring little comfort" to people with mental health problems and their loved ones.
He added: "The stark racial and social disparities in these statistics show how urgently we need reform to the Mental Health Act.
"The new UK government must pass an ambitious Mental Health Bill, that enshrines a right to assessment and treatment at an early stage, abolishes community treatment orders and addresses the overuse of restrictive, forceful practices."
He said people who are sectioned need therapeutic environments to get better in, and warned mental health hospitals are "too often crumbling and run-down, with some patients reporting floods, sewage leaks and rodent infestations".
The figures also reveal people in the most deprived areas of the country were more than three times as likely to be detained under the act than those in the least deprived.
Mr Patel said: "The Government must also tackle the underlying systemic risk factors of poor mental health, including poverty, racism, insecure housing and employment; to look at why so many of us are reaching crisis point.
"Bringing the Mental Health Act into the 21st century and prioritising preventative, equitable support must be at the top of the new government’s political agenda."
A Department of Health and Social Care spokesperson said the findings are "unacceptable" and added people with serious mental health issues "are not getting the support or care they deserve".
They added: "The Government is taking forward plans to improve mental health services within the NHS, including much needed reform to the Mental Health Act.
"Reform will make the Act fit for the 21st century, giving all patients more autonomy, dignity, and support."