A recent study challenged the conventional wisdom that suppressing negative thoughts is detrimental to our mental health. The findings, published in Science Advances, suggest that actively trying to push away fears and anxieties can, under certain conditions, actually reduce their intensity and make them less troubling, leading to improvements in mental well-being.
The research was initiated to address the longstanding debate on the effectiveness of thought suppression. Traditional psychological theories, based on Freudian concepts and modern cognitive perspectives, suggest that trying to suppress thoughts can actually make them more persistent, leading to increased emotional distress.
This view is contrasted with neurobiological evidence indicating that thought suppression can be beneficial, aiding in resilience against stress disorders like PTSD and reducing anxiety. The lack of experimental studies, due to ethical concerns about potential risks, left a gap in direct evidence on how thought suppression impacts mental health.
“We’re all familiar with the Freudian idea that if we suppress our feelings or thoughts, then these thoughts remain in our unconscious, influencing our behaviour and wellbeing perniciously,” said study author Michael Anderson, the head of the Memory Research Group at the MRC Cognition and Brain Sciences Unit in Cambridge.
“The whole point of psychotherapy is to dredge up these thoughts so one can deal with them and rob them of their power. In more recent years, we’ve been told that suppressing thoughts is intrinsically ineffective and that it actually causes people to think the thought more — it’s the classic idea of ‘Don’t think about a pink elephant.'”
The study included 120 adults from 16 countries. These individuals were recruited through various channels, including online advertisements and participant panels, and were screened for specific exclusion criteria such as a history of attention disorders or lack of fluency in English. To accommodate international participation during the COVID-19 pandemic, the entire study was conducted online via video conferencing platforms like Zoom and Skype.
These participants were then randomly divided into two main groups based on the type of thoughts they were to suppress: negative (fears and worries) or neutral events. This primary division created the foundation for examining the effects of thought suppression on different types of mental content.
To add depth to their analysis, the researchers further categorized participants into subgroups tasked with imagining positive or neutral future events. This segmentation allowed the team to explore how the suppression of certain thoughts interacts with the imagination of others, potentially affecting mental health outcomes.
Participants were then guided to generate 76 future events categorized as negative, positive, or neutral. These events had to be personal, vividly imagined, and plausible within the next two years. For each event, participants provided a cue word and a key detail, which would later serve as aids in the suppression and recall exercises.
Following event generation, the study embarked on a training procedure spread over five days, culminating in a series of tests and a follow-up session three months later. The core of the study involved guided exercises where participants practiced suppressing or enhancing thoughts of the generated events.
For the No-Imagine trials, participants encountered a cue word linked to a previously identified event. Initially, they were to recognize and briefly consider the corresponding event internally. Subsequently, while maintaining focus on the cue, they were instructed to actively halt any further contemplation about the event.
Participants were not to divert their attention with unrelated thoughts or engage in mental imagery of the event. Instead, their goal was to prevent any thoughts or visualizations triggered by the cue from forming. Within this setup, one group of participants worked on suppressing thoughts related to their negative events, whereas the other group concentrated on neutral events.
The researchers found that participants who underwent thought suppression training were able to successfully diminish the recall of suppressed thoughts, a phenomenon known as suppression-induced forgetting. This effect was observed for both negative and neutral thoughts, indicating that the act of suppressing thoughts can make them less accessible to memory.
Contrary to concerns that suppressing thoughts might lead to a paradoxical increase in their frequency or intensity—a phenomenon often cited in psychological literature—the study found no evidence of such rebound effects. Instead, suppressed thoughts became less vivid and emotionally charged, both in the immediate aftermath of the training and over the longer term.
“What we found runs counter to the accepted narrative,” Anderson said. “Although more work will be needed to confirm the findings, it seems like it is possible and could even be potentially beneficial to actively suppress our fearful thoughts.”
One of the most significant findings was the improvement in various mental health indices following the suppression training. Participants reported reductions in anxiety, depression, and negative affect immediately after completing the training sessions.
“It was very clear that those events that participants practiced suppressing were less vivid, less emotionally anxiety-inducing, than the other events and that overall, participants improved in terms of their mental health,” explained co-author Zulkayda Mamat. “But we saw the biggest effect among those participants who were given practice at suppressing fearful, rather than neutral, thoughts.”
These benefits were particularly pronounced for individuals with higher baseline levels of anxiety and for those experiencing posttraumatic stress related to the pandemic, suggesting that thought suppression may be especially helpful for people with heightened vulnerability to stress and emotional disturbances.
The study also observed that some of these mental health improvements, particularly the reduction in depressive symptoms, persisted for up to three months after the training.
While the findings are promising, the researchers acknowledge limitations in their study. The online nature of the training and the self-report measures used to assess mental health outcomes may not capture the full complexity of thought suppression and its effects. Finally, the participants were asked to suppress negative thoughts related to hypothetical events, which may limit the generalizability of the results to clinical contexts.
Future research is encouraged to explore the mechanisms underlying the potential benefits of thought suppression, to determine the optimal conditions and durations for suppression training, and to investigate the long-term impacts on mental health.
“This study challenges a widely accepted consensus in the therapeutic community that suppressing negative thoughts is harmful,” said María Cantero-García, a lecturer in psychology at the Universidad a Distancia de Madrid, who was not involved with the study, in an interview with the Science Media Centre.
“While the idea that suppression is counterproductive has been dogma, this research suggests that the reality may be more nuanced, highlighting that it does not always lead to negative outcomes. This seems to be partly related to the approach taken by third-generation therapies, such as Acceptance and Commitment Therapy (ACT), Mindfulness-Based Therapy (MBCT) and Dialectical Behaviour Therapy (DBT), which have particular approaches to thought suppression.”
“However, it is important to note some limitations,” Cantero-García noted. “The study may not address all situations and nuances, and its findings may not apply uniformly to all individuals or therapeutic contexts. In addition, more research is needed to fully understand the implications of these results.”
“In terms of the impact on individuals undergoing psychotherapy, this study could provide therapists with a more balanced understanding of negative-thought suppression. It could offer additional tools to help people deal with their thoughts effectively, always taking into account the circumstances and context. However, it is essential that therapists continue to assess each situation individually and consider the limitations and complexity of this issue in their clinical practice.”
The study, “Improving mental health by training the suppression of unwanted thoughts,” was published September 20, 2023.
