Correspondence Address:
Prof. Sandeep Grover
Department of Psychiatry, Post Graduate Institute of Medical Education and Research, Chandigarh
India

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In the last 1½ years or so, the COVID-19 pandemic emerged as a major challenge for humanity. Since the beginning of the pandemic, it became apparent that the elderly and those who have multiple comorbidities are at higher risk of development of COVID-19 infection, and when they develop so, they have more severe infection and poorer outcome.[1] Available data suggest that about 80% of deaths with COVID-19 infection occurred in those aged more than 65 years.[1] The medical conditions such as diabetes mellitus, hypertension, cardiac diseases, cancer, chronic obstructive pulmonary disease, those with liver diseases, human immunodeficiency virus infection, immunodeficiency diseases, hematological disease, are known to be associated with higher severity of COVID-19 infection.[1] Those with severe infection are more likely to be hospitalized and require intensive care unit (ICU) admission.[1] Emerging data also suggest that those admitted to ICUs with COVID-19 infection are also at higher risk of developing delirium,[2,3] which is a known risk factor for dementia. Besides being admitted to ICU, other factors associated with delirium in patients with COVID-19 infection include older age (>75 years), history of use of psychotropic medications, having a sensory impairment in the form of auditory and visual impairment, having stroke, and having Parkinson's disease.[3]

Emerging data also suggest that after recovery from COVID-19, many patients report the emergence of new-onset cognitive deficits. A large sample size study from the United States showed that >50% of the participants had difficulty in concentration and focusing and these were the fourth most common long-term symptom after recovery from COVID-19 infection.[4] Other studies have also shown a high prevalence of executive dysfunction, attention deficits, and memory disturbances in persons who have recovered from COVID-19 infection.[5],[6],[7] A large-scale study involving about 84,000 participants who were not having any symptoms of COVID-19 infection showed that even after controlling for age, gender, years of education, income, race-ethnic variations, and preexisting medical disorders, there is a high prevalence of cognitive deficits in the form of problems with attention, memory, and executive functions after recovering from acute infection.[7] Besides cognitive deficits, emerging data also suggest a higher prevalence of depression, anxiety, insomnia or sleep disturbance, dementia, and psychosis in patients who have recovered from COVID-19 infection.[8,9]

Most chronic medical illnesses, which are risk factors for COVID-19 infection, have also been reported to be a risk factor for the development of dementia. The 2020 Report of the Lancet Commission on Dementia Prevention identified 12 modifiable risk factors for dementia, which include lower education level, hypertension, diabetes mellitus, obesity, traumatic brain injury, hearing impairment, smoking, excessive alcohol consumption, depression, reduced physical activity, low social contact, and air pollution.[10] If one looks at these modifiable risk factors, it is evident that hypertension, diabetes mellitus, obesity, traumatic brain injury, smoking, excessive alcohol consumption, and depression are associated with an increased risk of developing COVID-19 infection. Further, due to the ongoing pandemic, there is a reduction in physical activity and social contact, in general. The only good thing that has possibly happened during the ongoing pandemic is reducing air pollution levels. Besides the higher prevalence of depression in patients who have recovered from COVID-19 infection, emerging data also suggest worsening glycemic control, especially in those who have received steroids.[11] Depression has also been identified as a consequence of the COVID-19 infection.[8,9]

Taken together, from the available evidence, it can be concluded that the COVID-19 pandemic has increased the risk of development of cognitive impairment and dementia. This would be more so in the elderly, who have a higher prevalence of risk factors for dementia, higher incidence of COVID-19 infection, higher rates of severe COVID-19 infection, and higher rates of admission to the ICUs due to COVID-19 infection. It can be said that soon, clinicians will encounter more and more persons with cognitive impairment and dementia. This calls for the implementation of recommended preventive strategies more vigorously to reduce the impact of COVID-19 on the cognitive reserve of people, especially those who already have a high prevalence of modifiable risk factors for dementia. This will involve screening all persons who have developed COVID-19 infection for psychiatric morbidity and cognitive deficits. In addition, those reporting cognitive deficits should be informed about the risk of dementia in the future and need to follow measures to address other modifiable risk factors, remaining cognitively active and following cognitive remedial measures as per the needs. As the COVID-19 situation eases, efforts must be made to minimize social isolation and improve physical activity levels. Besides these, during all the clinical encounters, the clinicians must make efforts to psycheducate the persons with noncommunicable diseases about the future risk of dementia and the need for optimal control and management of the illnesses.

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