ByLucy Notarantonio
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Many people recover from depressionbut continue to struggle with lingering symptoms such as memory problems, poor concentration and mental fog, which can affect work, relationships and daily life
Scientists are now exploring an unexpected way to tackle those cognitive struggles—and it involves a medication more commonly associated with gut health than mental health
The study, led by the University of Birmingham in collaboration with researchers at the University of Oxford in England, found early evidence that a prescription drug used to treat chronic constipation could help improve memory, attention and thinking speed in people with a history of depression
Dr. Angharad de Cates, corresponding author of the study from the University of Birmingham, told Newsweek: “This study provides solid proof-of-concept for future studies in people with current symptoms of mental illness, particularly in terms of the potential for broad cognitive benefits.”
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Brain Fog Often Persists After Depression
The findings, published in Psychological Medicine, suggest laxatives may target a lesser-known aspect of the condition often described as “brain fog.”
According to the National Institute of Mental Health, around 21 million U.S. adults have experienced at least one major depressive episode
Newsweek discussed the study with consultant clinical psychologist Dr. Bradley Powell, who was not involved in the research. He said brain fog is a frequently overlooked aspect of depression
“Brain fog is not a formal diagnosis, but it is a phrase many people use to describe feeling mentally slower, forgetful or unable to concentrate,” said Powell, the co-founder of Regal Private Therapy Practice, London. “In practice, it might mean reading the same email several times without taking it in, losing the thread of a conversation, forgetting appointments, struggling to organize tasks or finding relatively ordinary decisions unusually effortful.”
These cognitive symptoms can continue even after recovery, leaving people feeling as if they are not thinking as clearly or quickly as they once did
Researchers wanted to investigate whether a medication called prucalopride could help address those lingering issues
An Unlikely Medication
Prucalopride is already approved to treat chronic constipation. The drug works by activating a serotonin receptor known as 5-HT4, which is found not only in the gut but also in the brain
Because serotonin plays an important role in both digestion and brain function, researchers wondered whether stimulating this receptor could improve cognitive performance
The small experimental trial involved 50 adults who had experienced depression in the past but had recovered at least six months earlier. None were taking medication at the time of the study
Participants were randomly assigned to receive either the standard 2mg dose of prucalopride or a placebo for between seven and 10 days
Before and after treatment, participants completed a series of tests designed to measure memory, attention, processing speed and executive functioning—the mental skills used for planning, focusing and managing tasks
Those who took prucalopride performed better than participants who received the placebo. Researchers found they responded both faster and more accurately on cognitive assessments
“The results are encouraging but they are best understood as an early indication that deserves further study rather than evidence of a treatment that is ready for clinical use,” Powell said
He highlights how it was a small trial with a fairly specific group. He added: “It does not tell us whether the same effects would be seen in people who are currently depressed, taking antidepressants, older, or experiencing significant cognitive problems in everyday life.”
No Significant Side Effects Reported
Researchers reported no significant side effects during the study period
De Cates noted that participants did not experience serious gut-related complaints, explaining that prucalopride works as a laxative by gently stimulating bowel movements
The study assessed several aspects of cognition, including short- and long-term memory, working memory, attention and processing speed. When researchers combined the results, the prucalopride group showed higher accuracy and faster response times than the placebo group
Early Findings, but Promising
The researchers cautioned that the study was small and designed to provide early evidence rather than definitive answers. Larger studies will be needed to determine whether the benefits can be replicated and whether the drug could eventually play a role in treating depression-related cognitive symptoms
De Cates told Newsweek: “Our findings offer promise for addressing cognitive problems in depression, but this research area is still at the exploratory phase.”
De Cates added that prucalopride is already approved for constipation but it is still too early for people to use it as a treatment for cognitive symptoms
“We need dedicated clinical trials in this area before it can become a treatment option,” De Cates said
The team plans to continue investigating treatments for cognitive difficulties associated with major depressive disorder. Previous research has also suggested that drugs targeting the 5-HT4 receptor may help reduce the risk of depression, raising the possibility that this class of medication could offer broader mental health benefits in the future
Reference
De Cates, A., et al, (2026). “Common Constipation Drug May Help Clear Depression Brain Fog.” Psychological Medicine, https://www.sciencedaily.com/releases/2026/07/260712011751.htm. Accessed 17 July 2026
Contact Newsweek editors on this story: Charlotte Nisbet andJames Debens
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