How does early life stress affect health across the lifespan? This question has intrigued our research team for many years. People who experience early life stress, in the form of poverty, exposure to violence, noise, and other stressors, or who experience a harsh early family environment in the form of conflict-ridden, cold non-nurturant parenting, or neglect, have an elevated risk for illnesses, not only in childhood but throughout the lifespan; their adverse early experiences lead them to develop chronic diseases in adulthood earlier than is true for people who do not experience early hardships. These findings are somewhat mysterious, as it is not immediately clear why stress in one’s early life, during the first decade, would affect risk for illness in one’s 40s or 50s. Using a combination of laboratory experiments, large scale health studies, functional magnetic resonance imaging, and genetics studies, we’ve uncovered several of the reasons why.
The first pathway is alterations in biological stress regulatory systems. When people experience a great deal of stress early in life, the systems that regulate their responses to stress, such as the sympathetic nervous system (which affects heart rate and blood pressure) can show exaggerated responses to stress and may recover poorly following stressful experiences. With recurring or chronic exposure to stress, these stress regulatory systems can lose their resiliency (Taylor, Lerner, Sage, Lehman, & Seeman, 2004).
A second, related mechanism is that stress in the early family environment can influence mechanisms by which the brain manages stress. Using fMRI methodology, we found that growing up in a risky family environment has effects on processes involved in threat detection and in the regulation of responses to threat, in particular, involving amygdala reactivity and activity in the right ventrolateral prefrontal cortex (Taylor, Eisenberger, Saxbe, Lehman, & Lieberman, 2006). How the brain processes cues indicative of threat may increase stress responses chronically, leading eventually to adverse health outcomes.
Exposure to stress in the early environment also affects how people cope across the lifespan, and people who have experienced more stress early in life cope more poorly. They may ignore potentially threatening cues when they can, but overreact to stressors that they cannot avoid (Taylor, Eisenberger et al., 2006). In addition, their coping does not seem to be as successful for them as is true for people from nurturant families, inasmuch as both their psychological and biological stress responses can remain unaffected by their unsuccessful efforts to cope.
The early environment can also affect the expression of genes, and this may be another route to poor health. Certain genes may change the form in which they are expressed by virtue of the harshness of the early environment. For example, people who grow up in harsh early environments and who have certain genotypes that predispose them to depression may experience those effects more strongly (Taylor, Way, Welch, Hilmert, Lehman, & Eisenberger, 2006). Nurturance, by contrast, may actually protect people with the same genotypes against adverse psychological outcomes.
The early environment also affects whether you develop psychosocial resources for managing stress. For example, people who grow up in nurturant early environments are more likely to develop the psychosocial resources of social support from others, an optimistic outlook toward life, a sense of personal mastery, and high self-esteem. As a result of bringing these psychosocial resources to stressful events, they may experience stress less acutely and less often (Taylor & Broffman, in press; Taylor, Burklund, Eisenberger, Lehman, Hilmert, & Lieberman, 2008).
So, if people ask you, “Is it good to be optimistic? Is it good to have high self-esteem? Is it important to have a lot of friends, and do these resources have health effects?” the answer to all these questions is yes. If you would like to know more about these studies, you may visit the Taylor Lab at http://taylorlab.psych.ucla.edu/ or you may look at the following papers:
Taylor, S.E., & Broffman, J.I. (in press). Psychosocial resources: Functions, origins, and links to mental and physical health. In J.M. Olson and M.P. Zanna (Ed.), Advances in Experimental Social Psychology. New York: Academic Press.
Taylor, S. E., Burklund, L. J., Eisenberger, N. I., Lehman, B. J., Hilmert, C. J., & Lieberman, M. D. (2008). Neural bases of moderation of cortisol stress responses by psychosocial resources. Journal of Personality and Social Psychology, 95, 197-211.
Taylor, S. E., Eisenberger, N. I., Saxbe, D., Lehman, B. J., & Lieberman, M. D. (2006). Neural responses to emotional stimuli are associated with childhood family stress. Biological Psychiatry, 60, 296-301.
Taylor, S. E., Lerner, J. S., Sage, R. M., Lehman, B. J., & Seeman, T. E. (2004). Early
environment, emotions, responses to stress, and health. Special Issue on Personality and Health. Journal of Personality, 72, 1365-1393.
Taylor, S. E., Way, B. M., Welch,W. T., Hilmert, C. J., Lehman, B. J., & Eisenberger, N. I. (2006). Early family environment, current adversity, the serotonin transporter polymorphism, and depressive symptomatology. Biological Psychiatry, 60, 671-676.