We have long been told that our genes rule and there’s nothing much we can do about it. Even the latest research holds that our genes account for childhood anxiety, which in turn is the gateway to all future mental issues.
But now, an article in The New York Review of Books notes environmental factors that arise in early childhood can predetermine our future mental and physical health, including heart disease, cancer, mood and dietary disorders, alcohol and drug abuse, infertility, suicidal behavior, hyperactivity, learning deficits, and sleep disorders.
The basis for heritable environmental factors is that excessive stress or deprivation, whether experienced in early childhood or while in utero, affects our genetic programming by making long-lasting changes in the way our genes are expressed. By blocking access to certain genes, this mechanism can program us to experience future feelings of depression, anxiety or paranoia. And most surprisingly, these changes can be passed on to future generations that have never directly experienced the stresses or deprivations.
An example might be future obesity. The fetus, newborn, or child suffers continuing stress from hunger. But when food becomes available, the stress response cannot shut off, but continues as if the body thermostat is broken. Instead of feeling satiated when a certain amount of food is ingested, we keep craving more food. The long-term consequences can be inflammation, diabetes, heart-disease, schizophrenia and major depressive disorder.
Formerly, it was widely accepted that Darwinian evolutionary mechanisms were responsible for such long-lasting changes in brain function, but now we have evidence that epigenetic mechanisms can make such changes in the lifetime of a single person. The problem is that these changes may prepare us to be perpetually prepared for stresses and deprivations that no longer exist in a normalized environment.
The stresses and deprivations arising from natural disasters, famine, and the atrocities of war could contribute to a maladaptation on the part of this epigenetic mechanism, not just at the individual level, but among large groups, leading to psychological disease and ill health even when returning to a normalized environment. The most widely studied example was the Dutch Hunger Winter in 1944, when the Germans prevented food from entering. Children born during this had a high proportion of obesity and schizophrenia. Also, during the Great Chinese Famine (1958-1961), women who experienced famine gave birth to children with an uptick of schizophrenia and impaired cognitive function as adults, along with diabetes and hypertension.
Consistent with this view, we might ask if our current malaise of depression, anxiety and paranoia, reported to be at epidemic levels, could be the result of epigenetic mechanisms carried over from stresses and deprivations borne by our forebears. But since almost everyone’s forebears have suffered at one time or another from famine, economic deprivations, pestilence, and plagues, this pursuit can be pointless.
A more meaningful approach might be pinpointing and reversing the aberrant epidemic changes.
Source: Rosenfield I and Ziff E, New York Review of Books, Epigenetics: The Evolution Revolution, v LXV, n 10, Jun 7, 2018
This blog was co-published with Psychology Today, Campus Confidential, Coping with college