When should I be concerned about memory problems?
Not every instance of memory loss is worrying, but certain signs deserve prompt medical attention: sudden deterioration, the combination of memory and smell problems, or complaints that are already affecting daily life are reasons to call your general practitioner.
Memory problems that leave your daily functioning intact but are clearly noticeable to you or those around you can be an early warning sign. This is called mild cognitive impairment. The diagnostic bar is deliberately high: it involves a noticeable decline compared with a year earlier, confirmed by a doctor, yet you are still able to function independently. Not everyone with these complaints goes on to develop dementia, but it does justify a medical evaluation.
A sign that many people are unaware of is a declining sense of smell. In more than half of people aged 65 and over, the sense of smell diminishes. This is associated with memory problems and cognitive decline, and can be an early signal of Alzheimer's disease or Parkinson's disease. If you notice that smells are becoming fainter and your memory is also letting you down, that is a combination worth discussing with your doctor.
Sudden memory problems always deserve immediate attention. In a small number of people with a severe COVID-19 infection, an autoimmune condition of the brain has been described in which the immune system attacks the brain itself. This manifests as acute confusion, memory loss, and psychiatric symptoms. In the reported cases, patients improved following treatment. Conclusion: abrupt deterioration without a clear cause is a reason to see your general practitioner promptly.
For people with schizophrenia or non-affective psychosis, there is an additional signal: worsening attention and memory can herald a new psychotic episode. This does not apply to the general population, but it is relevant if you or someone in your immediate circle has that diagnosis. Finally, even if you have already had a TIA (mini-stroke), the available data do not mean you should automatically expect to develop dementia. A large long-term study found that TIA patients were not significantly more likely to develop dementia over twenty years, partly because they more often started taking medication and stopped smoking afterwards.
All claims are based on associative or observational studies; no randomised trials are available for this diagnostic question. The strength of evidence ranges from limited (COVID encephalitis, schizophrenia) to moderate (MCI, smell, TIA).