More than one in 20 people in the Forest of Dean were in contact with mental health services last year, new figures suggest.
The Mental Health Foundation warned the Government must "shift gears", otherwise people will be left struggling on long waiting lists for "overworked and underfunded" services.
Figures from the NHS annual mental health bulletin show about 5,620 people in the Forest of Dean were in contact with secondary mental health, learning disabilities and autism services at some point in the year to March.
It meant 6.3% of the 89,100 people in the Forest of Dean accessed mental health services, using the most recent population estimate for the area by the Office for National Statistics.
Across England, 3.8 million people accessed mental health services last year – accounting for 6.6% of the population and the highest number since records started in 2016-17.
The figures suggest a significant regional disparity, with 7.9% of the North East estimated to be in contact with services, while 5.5% of people in the South West were.
Alexa Knight, director of England at the Mental Health Foundation, said: "Far too often in the UK, we fail to adequately support people’s health – particularly their mental health - until they’re already knocking on their GP’s door.
"There’s been very little investment in the prevention of poor mental health over the past decade.
"Alongside both the pandemic and cost-of-living crisis pushing more people to experience mental health problems, so it’s no surprise more and more people are needing to seek help from NHS services for their mental health."
She said the Government should make it a priority to restore the Public Health Grant, funding given to local authorities to prevent ill health.
She added: "Without shifting gear, more and more people will be left to struggle for weeks, months and even years on waiting lists for overworked and underfunded mental health services."
Nearly 1.1 million children in England were known to be in contact with mental health services last year, including 1,710 in the Forest of Dean.
Minister for Mental Health, Baroness Merron, said: "I am pleased to see so many more people able to access support from our hard-working NHS mental health services. But too many people are struggling with poor mental health, made worse by the fact that waiting lists for support are far too long."
She added the Government is committed to "giving mental health the attention and focus it needs" by recruiting an additional 8,500 mental health workers to reduce delays and provide faster treatment.
She said: "By providing early intervention in every school and local community, we will take action to stamp out the root causes of mental-ill health and turn the tide on these distressing statistics."