This information is sourced from Dr Michael Zandi, Consultant Neurologist

Q. How should GPs approach a consultation with a patient complaining of ‘brain fog’?

A. The common reasons for cognitive impairment still apply. For example, in working age adults do keep thinking of possible psychiatric conditions such as severe depression, anxiety, drug and alcohol use and less commonly,  early signs of psychosis

Obtaining a collateral history is important and often more informative than doing a structured cognitive assessment. You can use a MoCA or MMSE. A MoCA has more of an emphasis on attentional issues

If memory problems appear to be focal, it warrants referral, for example focal problem may manifest as changes in language (e.g. understanding and expressing words) or amnestic symptoms with clear difficulties forming new memories

However more commonly, and I think this is what people mean by ‘brain fog’,  is that they have difficulty with their concentration and attention. This is hard to disentangle from anxiety. Most people that we have seen describing concentration and attention problems get better with time, so you can take a month or two to follow your patient up and see if these symptoms resolve

Q. How long would you expect brain fog to persist for and when should this be investigated further? Should patients be investigated if it has persisted for 3 months?

A. We don’t know how long brain fog persists for. We have seen some patients who were hospitalised with Covid who are still suffering with memory impairment 6 months later. I would refer patients with brain fog persisting for 3 months. Refer young and working age patients to neurology, and older patients to memory services. But obviously, GP should be guided by the presentation, so it is dependent on the severity, circumstances and the impact on changes in function. If patients need complex occupational health you may need to refer earlier say at 6 weeks

See also: How can we advise patients who complain of difficulty thinking clearly to approach their recovery?