A man rests his head on his hand looking clealry distressed as a friend holds onto his arm and tries to reassure himShare on Pinterest
Ruminating on unwanted thoughts may negatively impact mental health. Photography by Maskot/Getty Images
  • The belief that confronting unwanted thoughts will help a person process them better and that suppressing them is maladaptive has existed since Sigmund Freud.
  • However, research from the past two decades has suggested that learning to avoid certain unwanted thoughts could improve a person’s well-being.
  • A recent study has shown that training people to avoid unwanted thoughts can actually improve their mental well-being and reduce depression for up to three months afterward.

Can suppressing unwanted thoughts ever be a good thing? And do humans actually have to process every thought from the negative events they experience?

New research now indicates that, despite popular belief, it may be beneficial to suppress some unwanted thoughts, which could help improve mental health.

A recent study showed mental health could be improved for up to three months after online training to suppress unwanted thoughts.

The findings are published in Science Advances.

For this study, researchers from the Medical Research Council (MRC) Cognition and Brain Sciences Unit recruited 120 participants from 16 countries to take part in their trial, some via social media sites. They collected data on their mental health, and the cohort included participants both with a history and no history of mental health problems.

Participants were asked to list 20 negative “fears and worries” that could feasibly happen over the next two years that were of current concern to them, as well as 20 positive “hopes and dreams,” and 36 neutral events. They were then asked to give each a cue word that reminded them of the event and a key detail in the imagined scenario.

They underwent 20 minutes of training in thought suppression via videoconferencing, during which participants were confronted with their cue word for 4 seconds. Of the participants, 61 were in the “suppress-negative” group and asked to first imagine the event and then suppress any thoughts about it. Meanwhile, 59 participants in the “suppress-neutral” group were asked to imagine the event vividly. The participants were asked to do this 12 times a day for three days.

The researchers then measured how well the thoughts had been stored and assessed the mental well-being of the participants after they underwent the training. They then followed the participants up to three months later.

Immediately after suppression training, the participants who were asked to suppress unwanted thoughts were found to recall the key detail of the event they had been concerned about less often and less vividly. This was not the case for all participants.

However, of the 61 participants who were asked to suppress unwanted thoughts, six reported increased vividness of the unwanted thought after training.

At the three-month follow-up, the researchers found that participants who had been asked to suppress thoughts had lower vividness and recall of detail when thinking about the event they had been concerned about.

People with worse mental health symptoms at the start of the study were found to have a greater improvement in their mental health three months later, only if they had been asked to suppress thoughts.

The mental health indices scores of participants with PTSD who suppressed these thoughts increased by almost 10%, compared to a 1% fall among those who didn’t. These mental health indices included both negative impacts (e.g., anxiety, depression, worry) and positive impacts (e.g. positive effect on well-being).

How humans handle distressing thoughts, how different approaches influence mood and behavior, and whether or not that can be changed has been the focus of debate for over a century.

One of the most famous grandfathers of psychoanalysis, Sigmund Freud, made popular the concept that our motivations and behaviors are influenced by unconscious thoughts. He proposed psychoanalysis could help people by making them aware of them, and so the idea that confronting troubling thoughts was good for mental well-being became popular.

Whether or not you can actively suppress thoughts was explored over 30 years ago by Professor Daniel Wegner, a Harvard social psychologist who pioneered research into thought suppression. In his famous white bear experiments, he found that people who had been asked to avoid thinking about a white bear for five minutes were more likely to think about it afterward than those who had been told to think about it for the same length of time.

He proposed that consciously suppressing thoughts triggers a process that results in the thought occurring more frequently and that people who want to avoid unwanted thoughts should consider distraction, exposure therapies that aim to give the individual a sense of control over a fear, and mindfulness therapies which promote the ability to accept unwanted thoughts neutrally.

One researcher Professor Michael Anderson, senior scientist and programme leader at Cambridge Neuroscience, University of Cambridge, U.K. has focused on carrying out research showing that suppressing retrieval of unwanted memories can reduce the frequency of the memory.

In 2014, he published research showing that suppressing memories can inhibit their effect on a person’s awareness of them and ability to recall them, challenging the assumption that suppressed memories remain intact over time.

When the COVID-19 pandemic hit in 2020, his then Ph.D. student Dr. Zulkayda Mamat was unable to carry out the research she needed to. Both he and she recognized that there was a mental health pandemic occurring alongside the COVID-19 pandemic, and if they could develop an online tool to help people with many of the difficult scenarios posed by the pandemic, they could potentially make a difference. However, they wondered whether they were wrong about the potentially beneficial effect of suppressing unwanted thoughts.

“We had to overcome this hesitancy like, what if we really messed people up? [W]hat if training [trying] to get them to suppress their fears actually backfired and made them make those fears worse, and made them more mentally more poorly adjusted? [N]othing in our research in the last 20 years suggests that that’s going to happen. And so we thought, let’s take a risk,” Professor Anderson told Medical News Today in an interview.

The fact that many participants benefited from the training did not surprise Dr. Abigael San, chartered clinical psychologist and spokesperson for the British Psychological Society, who was not involved in the study.

“I didn’t think that what they did was that different to what happens in some types of therapy anyway,” she told MNT. She said this was likely because participants had been encouraged to confront the negative thought and then encouraged not to ruminate on it, which is known to cause problems.

The results of the study may not be generalizable, she added, as the cohort was made up of “a sample that isn’t necessarily representative of who we see in clinical populations.”

She said the results may not be “necessarily generalizable because these were people who participated in studies at the MRC,” and a small set of participants were recruited via online study advertisements on Facebook and Twitter and via word of mouth from previous participants.

The team now plans to do larger studies, including a clinical trial.

“Our immediate plans would be to maybe do a larger scale clinical trial of this intervention. So, this was an initial feasibility study. It wasn’t exactly small; we have a decent number of people. But I think for it to qualify as a current clinical trial, we have to look to engage in more formalities than we currently have. So, I think that’s my first order of business,” said Prof. Anderson.