Summary: “Brain fog”—the memory lapses and difficulty concentrating reported by up to 90% of people with major depressive disorder—has long been viewed as a possible early warning sign of relapse. A large new study challenges that assumption and reveals a surprising, more complex relationship between cognition and future depression risk.
Tracking nearly 1,800 participants, researchers discovered that among people with a history of depression, better cognitive performance was associated with a higher likelihood of relapse. This counterintuitive finding suggests that cognition and mood interact in ways that we do not yet fully understand.
Key Facts
- Study population: Data were drawn from the UK Biobank. The study matched about 1,862 participants with a prior episode of depression to an equal number of age- and sex-matched controls without a history of depression.
- Hypothesis: Investigators expected cognitive difficulties—often described as “brain fog”—to predict future depressive episodes.
- Relapse and incidence: One third (33%) of participants with prior depression experienced a depressive relapse during follow-up, while 13% of controls experienced a first episode.
- The paradox: In participants without prior depression, lower cognitive scores predicted a first depressive episode. For those with a prior episode, the pattern was reversed: higher cognitive scores correlated with greater relapse risk.
- Possible explanations: Researchers propose that stronger cognitive functioning might allow people to better notice and report symptoms, increasing recorded relapse rates. Alternatively, higher-functioning individuals may face greater workplace or social stressors that raise relapse risk.
Source: University of Birmingham
Overview
Published in BMJ Mental Health, the study was led by Dr Angharad de Cates at the University of Birmingham with collaborators at the University of Oxford. The team analysed cognitive testing, clinical records, and MRI data for participants recruited through the UK Biobank.
Funded by the Guarantors of Brain and the National Institute for Health and Care Research (NIHR), the study explored whether persistent cognitive impairments—experienced by 70–90% of people with major depressive disorder (MDD) and lasting in about 40%—could help clinicians predict who is most likely to experience another episode.
Participants completed a battery of cognitive tasks—reaction time tests, memory exercises, and reasoning tasks—and underwent structural and functional MRI to assess brain anatomy and connectivity. The researchers combined task results into a composite measure of general cognitive functioning and examined associations with later depression using regression and survival models that adjusted for key confounders.
Across the sample, those with remitted depression faced substantially higher risk of future depression than controls. But analyses examining cognition revealed contrasting patterns: in controls, lower composite cognitive scores predicted greater incidence of new depression; in the remitted-depression group, higher cognitive scores were associated with increased relapse risk. Task-level measures of executive function, processing speed and reasoning contributed to these effects.
Neuroimaging showed that greater grey matter in regions of the default mode network correlated with better concurrent cognitive performance, but imaging measures added little predictive power for future depression risk.
Dr Angharad de Cates commented that the team had expected poorer cognition to signal higher relapse risk across both groups. Instead, findings were nuanced: “Among people with previous depression, those with higher cognitive scores were more likely to experience a further depressive episode than those with lower scores—the opposite pattern to that observed in controls.”
She highlighted that the result points to multiple social and residual factors tied to cognition that deserve more research. One practical implication is that better cognitive function may enable people to recognise symptoms earlier and seek help, underscoring the need to optimise cognition during recovery while still monitoring relapse risk.
What about healthy controls?
In participants without a prior diagnosis, poorer cognitive performance increased the likelihood of experiencing a first depressive episode. Although the absolute incidence was lower for this group (13%), those with weaker cognitive scores showed a roughly 40% higher risk relative to baseline. This supports the idea that cognitive deficits can precede and potentially signal a first onset of depression.
Dr Anya Topiwala of the University of Oxford noted that memory problems are often seen as a consequence of depression, but the relationships are bidirectional and complex. She emphasised that remitted depression remains a high-risk state and that relapse risk varies between individuals, suggesting a role for more personalised prevention and follow-up strategies.
The research team, part of the Midlands Mental Health Mission and supported by the NIHR Biomedical Research Centre: Oxford Health, is continuing to investigate interventions to address cognitive deficits common in MDD that affect short- and long-term memory, attention, and concentration.
Key Questions Answered:
A: No. Cognitive impairment remains a significant burden for many patients. The study indicates that cognitive scores alone do not reliably signal relapse risk for people with a history of depression the way they might for predicting a first episode in those without prior illness.
A: One possibility is that people with stronger cognition have more capacity for self-reflection and thus are likelier to recognise and report symptoms. Another is that high-performing individuals often face more demanding environments that create stressors linked to relapse.
A: No. Restoring memory and focus is a positive recovery goal. Clinicians should, however, recognise that remission does not eliminate relapse risk, and monitoring should continue even when cognitive function appears to have returned.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The underlying journal paper was reviewed in full.
- Additional context was provided by staff summarising the research and implications.
About this cognition and depression research
Author: Tim Mayo
Source: University of Birmingham
Contact: Tim Mayo – University of Birmingham
Image credit: Neuroscience News
Original research: Open access. “Cognition and Future Depression: Associations with Risk in Those With and Without a History of Depression” by Angharad N. de Cates et al., BMJ Mental Health. DOI: 10.1136/bmjment-2025-302332
Abstract
Cognition and Future Depression: Associations with Risk in Those With and Without a History of Depression
Background
Cognitive impairments commonly accompany depression and often persist after mood symptoms improve. The connections between cognitive performance, brain structure and function, and later depression risk remain unclear, limiting prevention strategies.
Objective
To determine whether cognitive measures are associated with subsequent depression risk, both for relapse after remission and for first-episode occurrence.
Methods
The study compared 1,862 UK Biobank participants with remitted ICD-10-defined depression (mean age 52.7 years) to 1,862 matched controls without depression history. Cognitive performance was assessed at composite, domain, and task levels. MRI-derived measures probed brain networks and connectivity. Longitudinal relationships with future depression were analysed using logistic regression and Cox models adjusted for confounders.
Findings
Remitted participants had a higher risk of future depression (33%) compared with controls (13%). In controls, better composite cognition predicted lower future risk; in remitted participants, better cognition predicted higher relapse risk. Executive function, processing speed and reasoning contributed to these patterns. Greater grey matter in default mode network regions associated with better concurrent cognition but did not predict future depression. Overall, imaging added limited predictive value.
Conclusions
A history of depression confers markedly increased risk of future episodes. Cognitive performance relates to future depression in opposite directions depending on prior history. Neuroimaging measures offered little additional prediction.
Clinical implications
Assessing relapse risk should consider an individual’s depression history. Lower baseline cognition may signal higher first-episode risk in those without prior depression, while among people in remission, relatively higher cognitive performance may be associated with greater likelihood of reporting future depressive symptoms. Personalised monitoring and prevention strategies are warranted.