Characterizing predictors and chronicity of brain fog in long COVID, 2025, Staggs et al.

[SNT Gatchaman]

Characterizing predictors and chronicity of brain fog in long COVID
Staggs; Furst; Mills-Finnerty

Long COVID is a chronic illness that persists following COVID-19 infection, with fatigue and brain fog as the most frequent complaints. However, there is no objective case definition for brain fog in long COVID and chronicity of symptoms remains unclear.

This study recruited two waves of participants: those with a history of COVID-19, who participated in 2023 (N = 793, age = 38.5 ± 13.2, 44% female, 35.1% long COVID) and a follow up cohort collected in 2024 of participants who qualified as having long COVID at time point 1 (N=119, 61 female, 58 male). Participants completed questionnaires and cognitive tasks from home. We trained a binary classification model for long COVID diagnosis (73% accuracy) and a linear regression model for cognitive complaints (RMS error 5.8).

A long COVID diagnosis at timepoint 1 was classified by biopsychosocial variables including stress, social support, and sex (women more likely). Symptom clustering revealed that phenotypes with both mental and physical health symptoms were predictive of brain fog, but not phenotypes with only sleep-related or physical symptoms. Markers of brain fog included slower reading and typing, slower reaction times in cognitive tasks, and changes in information processing speed and thresholds for making choices. Timepoint 2 data showed that the majority (82.4%) of participants did not remit from long COVID.

These findings highlight the complex biopsychosocial factors that predict having long COVID with brain fog, and the need for interventions to improve remission rates.

HIGHLIGHTS
• Long COVID diagnosis is predicted by biopsychosocial factors.

• Brain fog in Long COVID is related to both mental and physical health symptoms.

• Brain fog has objective cognitive correlates.

• Remission rates for Long COVID in a follow up sample was 14.3%.

Web | DOI | Psychiatry Research | Paywall

 

[SNT Gatchaman]

Conclusion —

Our results demonstrate that both meeting criteria for long COVID and subjective cognitive complaints are both predicted by a diverse set of biopsychosocial factors. Clustered phenotypes suggest that mixed mental and physical health symptoms are more related to cognitive complaints than physical or sleep complaints alone.

We were able to identify objective cognitive markers of subjective cognitive complaint severity using a brief, remotely delivered battery in a large sample. This provides important evidence that brain fog is not merely a change in perceived cognitive function, but rather that it correlates to specific differences in objective cognitive function and that it can potentially be characterized using short objective tests. Slow reading, typing, and reaction times in the visual search and remote associate tasks are all related to increased PROMIS Cognition scores (i.e., higher dysfunction).

Our longitudinal follow up indicated low remission rates (14.3%) and high chronicity and symptom burden, highlighting the need for effective treatments to promote recovery.

 

[rvallee]

Long COVID diagnosis is predicted by biopsychosocial factors.

They don't.

These findings highlight the complex biopsychosocial factors that predict having long COVID with brain fog, and the need for interventions to improve remission rates.

Also no.

Might as well say that a questionnaire that asks people "do you have a headache right now?" can predict headaches. This feels like work that should have been done mostly using lego blocks and finger paint.

I have yet to see a single biopsychosocial study that adds anything useful, and this study would actually be better if they had ignored that and simply did their evaluations without any preconceptions.

Exactly as useful as this, except worse, and not in a practical way:

 

[Sean]

A long COVID diagnosis at timepoint 1 was classified by biopsychosocial variables including stress, social support, and sex (women more likely).... ​

​

These findings highlight the complex biopsychosocial factors that predict having long COVID with brain fog, and the need for interventions to improve remission rates.​

Where in the causal chain do stress and social support lie? Cause or consequence of LC? Exacerbating secondary contingent post-onset factor that features in the management of most medical conditions – e.g. how well do cancer patients do with more stress, less social support (including economic)? Why is psycho and social always conflated together? Social covers an awful lot of ground, well beyond psycho. Etc.

And sex is as much a biological factor as anything else. Maybe, like it appears for ME/CFS, simply being biologically female is a risk factor independent of anything else?

 

[rvallee]

And sex is as much a biological factor as anything else. Maybe, like it appears for ME/CFS, simply being biologically female is a risk factor independent of anything else?

I caught that too. Biopsychosocial is such a hollow and useless construct that they have to take factors that are a coin flip and have massive strictly biological implications in order to find anything relevant.

Medicine really hasn't changed from this. Mostly because humanity hasn't.