Sigmund Freud, the father of psychoanalysis, had a simple idea about dealing with upsetting thoughts: better out, than in.

In other words, don’t try to suppress distressing thoughts. Talk them to death, instead.

Therapists have been following that advice for more than a century.

Why? Because the prevailing theory holds that thought suppression is maladaptive. The problematic thoughts will cut through anyway.

Freud proposed that suppressed thoughts persist in the unconscious mind, resurfacing indirectly through symptoms and dreams.

According to modern theory, suppressed thoughts eventually rebound. And when they do, they become more vivid and emotionally intense. This serves to amplify a person’s distress.

Hence the old theory has stuck: better out, than in.

But a new study – from Cambridge University’s MRC Cognition and Brain Sciences Unit – turns that theory on its ear.

What the researchers say

In a paper published by Science Advances, and openly available to the public, the researchers come out with guns blazing:

“We challenge the view that thought suppression worsens mental illness.

“We hypothesized, in contrast, that training people to suppress unpleasant thoughts in response to reminders would improve their mental health, even in people with anxiety, depression, and PTSD.”

The fundamental motivation for the study was to find an effective response to the mental health crisis spawned during the COVID-19 pandemic.

As one of the researchers, Dr Zulkayda Mamat, explains:

“Because of the pandemic, we were seeing a need in the community to help people cope with surging anxiety.”

There was already a mental health crisis, she said, “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”.

And that’s what they did

In a novel experiment, 120 adults from 16 countries underwent three days of online training to suppress either fearful or neutral thoughts.

In the study, according to a statement from Cambridge, each participant “was asked to think of a number of scenarios that might plausibly occur in their lives over the next two years”.

They had to name:

• 20 negative ‘fears and worries’ that they were afraid might happen – such as the death of a loved one, or visiting a parent in hospital.
• 20 positive ‘hopes and dreams’ (travelling the world)
• And 36 routine and mundane neutral events (hanging out the washing).

The fears had to be worries they were dealing with at the time: the sort of worries that repeatedly intruded their thoughts. For each scenario they were provide a cue word as a reminder that could be used to evoke the event during training.

They were also given a key detail (a single word expressing a central event detail).

Participants were asked to rate each event on a number of points, including vividness, likelihood of occurrence, level of anxiety about the event, and emotional intensity.

Participants also completed questionnaires to assess their mental health. However, no one was excluded. This allowed the researchers to look at participants with a broad variety of issues, including serious depression, anxiety, and pandemic-related post-traumatic stress.

All of this was the set-up before the actual training.

In short, the participants were confronted with cue cards that signalled various events.

While continuing to stare directly at the reminder cue, “they were asked to stop thinking about the event… and to block any images or thoughts that the reminder might evoke”.

For more about what was involved with the experiment, see here.

The findings

Suppressing negative thoughts did not lead to a ‘rebound’, where a participant recalled these events more vividly.

Instead, suppression “reduced memory for suppressed fears and rendered them less vivid and anxiety provoking”.

After training, participants reported less anxiety, negative affect, and depression “with the latter benefit persisting at three months”.

The researchers were concerned that “suppression training may harm those with anxiety, depression, and posttraumatic stress”.

However, “contrary to the foregoing concerns, participants reporting higher trait anxiety and posttraumatic stress benefitted the most from suppressing their distressing thoughts”.

Even so, the researchers conceded that suppressing thoughts might be harmful for some people.