Biological markers of aging and mental health: A seed and soil model of neurocognitive disorders.

As the population of the world gets older, cognitive and mental health decline in older adults has become one of the most pressing scientific problems of the 21st century. It has been well-established that multiple pathways exist that can lead to future cognitive decline and the development of age-related mental health conditions. Making matters more complicated is the fact that aging is not a homogenous or simple process; rather, each person brings a diverse set of circumstances to the table, leading to differences in biologically aging. Research is needed to identify how the intersection of environmental and biological factors may protect older adults or put them at future risk for cognitive decline and the development of age-related mental health conditions. Furthermore, each potential factor may impact different domains of cognition and mental health or may impact individuals differentially based on genetic, environmental, social, emotional, and behavioral factors. Neuroimaging is one key tool that can be used to discover and assess markers of cognitive and mental health. The goal of this special issue is to expand the science on how biological markers can aid the understanding of aging and mental health through the lens of the individual from an international perspective, representing Germany, Taiwan, Thailand, the United Kingdom, and the United States. Common themes from these articles are used to support the new Seed and Soil Model of Neurocognitive Disorders.