Abstract
Why do some people get sick, and others do not? This basic question, of vulnerability and resilience, is of crucial importance in physical and mental health research. Determining factors that impart resilience, or contribute to vulnerability, could be a turning point in our fundamental understanding of disease. This collection explores current data on the role of two systems that seem indispensible for health: Circadian rhythms, and Sleep. While we have learned a great deal about the mechanisms that control these two biological processes, we are only at the beginning of our understanding of how these systems impact mood, cognition, immune function, and metabolism. The concepts of resilience and vulnerability may be useful in understanding the myriad effects of circadian rhythm and sleep disruption on mental and physical health, and perhaps provide new insights to how we can predict - and protect against - negative outcomes while amplifying positive health effects.