Sigmund Freud was the first ­person who proposed the idea that suppressing negative thoughts was bad for your mental health. His belief led to a school of thought that dredging up trauma from your past was good for you. Well, maybe not.

Cambridge University scientists have turned Freud’s theory on its head and trained 120 volunteers worldwide to actually suppress thoughts about worrying negative events.

And hey, not only did the thoughts become less vivid, but the participants’ mental health improved as well.

When Covid-19 arrived in 2020, Cambridge professor Michael Anderson wanted to see how his research could help people through the pandemic.

His interest lay in a brain mechanism known as inhibitory control – the ability to override our immediate reactions – and how it might stop negative thoughts surfacing when confronted by reminders of them.

Dr Zulkayda Mamat, then a PhD student in Professor Anderson’s lab, believes inhibitory control is critical to overcoming trauma. Could it be learnt? Could it be taught? Dr Mamat said: “Because of the pandemic, we were seeing a need in the community to help people cope with anxiety.

“There was already a mental health crisis, a hidden epidemic of mental health problems, and this was getting worse. So with that backdrop, we decided to see if we could help people cope better.”

Professor Anderson and Dr Mamat recruited 120 people across 16 countries to test their theory.

Each participant was asked to think of 20 negative fears and worries, 20 positive hopes and dreams, and 36 neutral events.

A cue word was chosen as a reminder of the negative thought and a key detail as a central event. For example:

■ Negative – visiting parents with Covid at the hospital, with the cue “Hospital” and the detail “Breathing”.

■ Positive – seeing your sister get married, with the cue “Wedding” and the detail “Dress”.

Then, over Zoom, Dr Mamat trained participants in ‘no-imagine trials’ where they tried to block any images or thoughts, and ‘imagine trials’, where they imagined how they would feel at the event. Their level of anxiety was measured on the third day and at three months.

Questionnaires about anxiety, worry and wellbeing were completed.

Dr Mamat said: “It was very clear that those events that participants practised suppressing were less vivid, less emotionally anxiety inducing, than the other events, and that overall, participants improved in terms of mental health.

“But we saw the biggest effect among those participants who were given practice at suppressing fearful, rather than neutral, thoughts.”

That’s a useful change of heart.