Hundreds of patients were waiting for routine treatment at Cornwall Partnership Trust in November, figures show.
It comes as the King's Trust health charity said it will be a challenge to meet the Government's latest pledge to reduce waiting lists by the end of the year.
NHS England figures show 356 patients were waiting for non-urgent elective operations or treatment at Cornwall Partnership NHS Foundation Trust at the end of November – down from 503 in October, and 847 in November 2021.
Of those, 11 (3%) had been waiting for longer than a year.
The median waiting time from referral at an NHS Trust to treatment at Cornwall Partnership Trust was five weeks at the end of November – down from six weeks in October.
Nationally, 6.9 million people were waiting to start treatment at the end of November.
Siva Anandaciva, chief analyst at the King’s Fund, said there was “no shying away from the reality that the NHS is deep in crisis”.
Ms Anandaciva added: “While there are huge delays in admitting patients, there are also serious issues in discharging patients – with over 13,000 people stuck in hospital despite being medically fit to leave.
“Meanwhile, the waiting list for planned hospital care remains stubbornly over 7 million and cancer services are also under pressure, which underlines the challenge in meeting the Government’s latest pledge to reduce waiting lists by the end of 2023.”
Separate figures show 1.6 million patients in England were waiting for a key diagnostic test in November – a rise on 1.5 million in October.
At Cornwall Partnership Trust, 164 patients were waiting for urodynamics tests.
Of them, 125 (76%) had been waiting for at least six weeks.
Cancer Research UK chief executive Michelle Mitchell said the figures “paint an extremely troubling picture for people affected by cancer”, adding: “The last time all targets for cancer waiting times were met was as far back as 2015, and the number of people waiting for diagnosis and treatment remains unacceptably high.
“It can be easy to get lost in statistics – but each one of those numbers represents someone’s child, parent, partner, sibling or friend.”
NHS national medical director, Professor Sir Stephen Powis, said: “The NHS will keep its foot on the accelerator to continue to make progress on the Covid backlog and hospitals have today been asked to ensure anyone waiting longer than 18 months has their treatment booked in before March.”