Researchers Propose New Definition of Brain Health

In correspondence published in The Lancet Neurology, researchers proposed a new definition of adult brain health.

Brain health in adults should be defined as a “state of complete physical, mental, and social wellbeing through the continuous development and exercise of the brain,” according to a new definition proposed in a letter published in The Lancet Neurology.

More than 70 years ago, the World Health Organization (WHO) defined health as “a state of complete physical, mental, and social wellbeing and not merely the absence of disease or infirmity.” While brain health plays a major role in health, there are no objective methods to quantify it and the current definitions do not take into account mental health, wellbeing, and happiness.

The broad-scope definition of brain health proposed in the letter may impact the definition of dementia, as a combined set of neurological, mental health, and wellbeing core elements will unify the various fields and help to understand their interactions.

Previous studies have supported the unified approach. A study from Canada showed that implementation of a stroke prevention strategy was associated with a decreased incidence of both stroke and dementia. A study to assess for environmental,

socioeconomic, and individual risk and protective factors contributing to these declines in incidence is underway.

Management of risk factors has been the main route to prevent disease, but additional physical, psychological, and socioeconomic measures are needed to enhance brain health. The increased digital connectivity during the COVID-19 pandemic may support new strategies to improve brain health.

“Convergent, synergistic efforts, focusing on better brain health now, can take us a step closer to the WHO definition of health,” concluded the researchers.


Hachinski V, Avan A, Gilliland J, Oveisgharan S. A new definition of brain health. Lancet Neurol. 2021;20(5):335-336. doi:10.1016/S1474-4422(21)00102-2