The protest outside Meadowfield Hospital in Worthing on Saturday

Figures obtained from the Sussex Partnership NHS Foundation Trust under a Freedom of Information Act reveal that 837 treatments were administered in 2018/19, compared with 238 treatments in 2011/2012.

A single patient may receive between three and 12 treatments, with the majority of patients receiving 12 treatments, the trust said.

ECT involves sending an electric current through the brain, causing a seizure, in order to relieve the symptoms of some mental health problems, according to the mental health charity MIND.

It can be used to treat people with severe or life-threatening depression.

According to the charity, it can sometimes cause memory loss, which is often short-term, but can be longer-lasting as well.

A spokesman for the Sussex Partnership NHS Foundation Trust said it used ECT in line with national guidelines set out by the Royal College of Psychiatrists.

It said the decision to offer ECT was always discussed in full with the patient, their family and carers.

Patients are supported throughout by an experienced team of professionals who provide comprehensive information about the procedure so that they can make an informed choice about their treatment, the spokesman said.

On Saturday, members of the Citizens Commission on Human Rights, which was founded by members of the Church of Scientology in 1969, protested the use of ECT outside the hospital.

The group, which obtained the figures on treatments at the hospital, is against ECT because it claims there is a risk it damages brain cells and want it to be banned.

But a spokesman for the NHS Trust said it ECT was ‘a safe and effective evidence-based treatment for people living with severe depression’.

“We are extremely concerned about the language that this group has used,” the spokesman said.

“We are particularly worried about the unnecessary distress that this may cause patients and their families and urge them to seriously reconsider their language.

“The last thing we want is for anyone being offered ECT to feel anxious or worried about their treatment.