A Jolt to What We Believe

This piece originally appeared on Psychology Today.

It is never easy to confront something that challenges a deeply held belief. One could feel, for instance, the collective sigh of relief among physicists in September when a study showed that  antimatter particles fall down when released, thus demonstrating that they are subject to the same gravitational force as particles of ordinary matter. This finding represented the resolution of a long-standing question in physics; the opposite finding would have meant the need to revise fundamental laws of physics. Scientists are clearly not immune to the anxiety we all feel when something we are sure is true may not be.

Consider what happens when we ask readers of this article not to think about elephants. That instruction to suppress a thought inevitably leads to intrusive thoughts of elephants that one cannot in fact suppress. This rebound effect suggests that telling someone to suppress a thought leads to an increase in thinking about it.

 What to do then with the recent report in the journal  Science Advances that suppressing negative thoughts may have mental health benefits? As United Kingdom authors Zulkayda Mamat and Michael C. Anderson note, the fields of psychology and psychiatry have long held to the notion that a road to treating some forms of mental illness, like anxiety disorders, posttraumatic stress disorder (PTSD), and depression, is to “make the unconscious conscious.” Freud of course believed that repression of traumatic events into the unconscious is a cause of psychological symptoms and invented the procedure of psychoanalysis in part to retrieve these memories to help the sufferer exert greater control over them. More recently, using the paradigm of Pavlovian fear conditioning in rodents, it has been argued that there is a molecular basis to this idea and that making unconscious traumatic memories available to conscious manipulation before they are reconsolidated in memory may be therapeutic (see for example Gorman JM,  Neuroscience at the Intersection of Mind and Brain, Oxford University Press, 2018).

Suppressing Negative Thoughts Found Beneficial

Now, however, the long-held belief that suppressing painful memories is harmful is challenged by Mamat and Anderson’s study. In this carefully conducted work, conducted via Zoom, they recruited 120 people, 93% female, and asked them to identify negative, neutral, and positive thoughts, each with single-word reminder cues. They then trained 61 of them to suppress the negative and 59 of them to suppress neutral thoughts over a three-day training period. Measures of various components of mental health were collected before, immediately after, and three months after the experiment was conducted.

They then presented the negative and neutral memory cues to the participants in the respective groups and asked them to suppress their thoughts about them. The results of the experiment are clear and startling. The participants were indeed successful in suppressing both negative and neutral thoughts and, contrary to the example of trying to suppress the thought about elephants (and there you go again, thinking about them), there was no rebound effect among the participants in the negative memory suppression group. More surprising, the people in the negative memory suppression group, as compared to those in the neutral memory group, experienced improvements in ratings of several measures of anxiety and depression, which they attributed to their ability to suppress negative thoughts, and which were sustained three months later.

Even among those in the group who at baseline scored high on measures of anxiety and pandemic-related posttraumatic stress disorder symptoms experienced improvements in those symptoms and in overall mental well-being. Contrary to expectation, focusing on positive thoughts had no such effect on improving mental health measures in any of the research participants.

Negative Thought Suppression Could Be a New Therapy

Mamat and Anderson conclude that “the substantial and durable mental health benefits, safety, high endorsement, spontaneous use, and accessible delivery make suppression training a promising and scalable intervention on its own or as a neurobiologically grounded complement to standard treatments such as exposure or cognitive behavioral therapy.” Thus, they suggest that training people with anxiety disorders, PTSD, and depression may be a viable new therapeutic approach. This of course challenges long standing beliefs among many in the fields of psychology and psychiatry and even in the neuroscience community that suppressed thoughts are invariably harmful and must be released into consciousness to effect therapeutic improvement.

Of course, this work must be replicated before we jump to developing new therapies and, as  Mamat is quoted as saying, it is not clear that thought suppression would be helpful with all types of negative thoughts or with every person suffering from a mental health condition. “There are some thoughts that you try to think about and process and deal with, but there are other thoughts about the future you can’t do anything about and suppressing them could help,” he says. It is important to note that none of the research participants in this study was actually diagnosed with a mental health disorder as part of the study but rather that some of them scored higher than others on measures of mental health. Hence, whether thought suppression works in clinical situations remains to be studied.

 Here is a good example of a significant challenge to a long-held scientific belief. Unlike in the case of the discovery that antimatter particles fall down because of gravity, behavioral scientists will now have to grapple with this potential paradigm shifter. Physicists were left at least temporarily off the hook for having to reimagine their basic concepts in September, but psychologists and psychiatrists were not. It will be fascinating to see how they deal with this study. Will the anxiety it provokes cause some to try to suppress its significance or will a substantial number embrace the findings and move to further study them? Considering the needs of people suffering with anxiety disorders, PTSD, and depression, we certainly advocate for the latter course.