Feeling depressed is the main reason behind three trips to A&E a day at Milton Keynes University Hospital, figures suggest.
Mental health charity Mind said it was "deeply concerning" to see so many people, nationally, needing emergency care for this reason.
NHS Digital data shows in the year to March, "feeling depressed" was a patient's chief complaint in 1,060 attendances at Milton Keynes University Hospital NHS Foundation Trust – an average of three a day.
The chief complaint is what a clinician views, during a patient’s first assessment, as the main reason that drove them to seek emergency care, but is not an official diagnosis.
Across England, trusts recorded 114,000 A&E attendances in which a patient was initially recorded as feeling depressed in 2020-21.
It was the 28th most common reason – of nearly 150 recorded – for heading to an emergency department nationally last year, coming above puncture wounds, back injuries, coughs and sore throats.
Different figures show "depressive disorder" was listed as the first suspected or confirmed diagnosis in 295 A&E attendances at Milton Keynes University Hospital NHS Foundation Trust in 2020-21.
NHS trusts in England recorded 83,500 attendances where a diagnosis of depressive disorder was given to patients in A&E over the same period.
A patient with this diagnosis may not necessarily have been recorded as “feeling depressed” in their initial assessment.
To protect patient confidentiality, numbers are rounded to the nearest five.
Leila Reyburn, policy and campaigns manager at Mind, said: "It is deeply concerning to see so many people feeling so mentally unwell that they need to go to A&E.
"This is supported by data which shows an increasing number of people, including children, being treated by the NHS in a mental health crisis.
"Many people have seen their mental health worsen during the pandemic, which is why it is vital the Government uses the upcoming Spending Review to fund mental health services, so that people can get help early on, before they find themselves in an emergency."
The Government said its NHS Mental Health Implementation Plan sets out the need for the mental health workforce to grow by over 27,000 by 2023-24.
A Department of Health and Social Care spokesperson said: "It is vital that everyone can get the right support when they need it and we are delivering the fastest expansion in mental health services in NHS history, backed by an additional £2.3 billion a year by 2023-24.
"This will benefit hundreds of thousands more people."
The spokesperson added the Government had spent an extra £500 million to help those whose mental health has been impacted by the pandemic, as well as establishing 24/7 urgent helplines at all NHS mental health providers.
An NHS spokeswoman said: “As part of the NHS Long Term Plan, the NHS is expanding mental health services, including talking therapy services for people suffering from anxiety and depression."
She said anyone needing help can self-refer online, contact an urgent 24/7 mental health helpline or access advice through the Every Mind Matters website.
"In addition, anyone who needs to attend A&E with mental health needs should receive expert, compassionate mental health care, with all A&E departments now equipped with specialist mental health liaison teams on-site," the spokeswoman added.