In 1984, when I started graduate school in psychology, researchers were just beginning to look at the interaction between nature and nurture to understand what led to the development of mental illness. Throughout the 1950′s most mental illness was understood to fall squarely on the shoulders of mothers – terms like the schizophrenogenic mother were used to describe a rejecting mother who caused schizophrenia in her offspring. In the late 1960′s, the medicalization of mental illness began to take hold, and now, 40 years later, most mental illness is seen as biologically based.
I always believed illness, mental or physical, was the result of a subtle interaction between genetic coding and environmental factors. In the 1980′s this notion was referred to as the transactional theory, meaning multiple interactions over a lifetime led to health or illness.
In this decade, this idea is known as epigenetics. It turns out human development is not hardwired in DNA. Epigenetics is the interface between nature and nurture. Epigenetic changes are biological markers on DNA, which modify gene expression without altering the underlying sequence. Researchers have found that environmental factors — such as trauma, stress and even diet — can activate epigenetic changes. Epigenetic traits can be passed from one generation to the next. Epigenetics nullifies the nature-nurture debate, because your genes are powerless without your epigenetic software directing them when, where, and how to work.
Long before the term epigenetics was coined, the concept influenced my thinking. While I believed one could have a genetic predisposition to an illness and never develop the full-blown illness, I did not know which genes could be influenced and which, like eye color, were fixed and immutable. For example, I knew I had a genetic marker for obesity. If you look at photos of my ancestors, they were zaftig women and men. And they developed illnesses we know are correlated to obesity – diabetes, hypertension, cardiovascular disease, first my grandparents, then my parents. Genetics 101. Things were laid out. Or maybe not.
What if my genetic code was not my destiny? If everything is predetermined at birth, where does free will enter into our lives? Why bother making decisions about how we lead our lives, if everything is already mapped out in our genes?
Nine years ago, my doctor said I was heading down the diabetes path. I had been on the obesity path for twenty years. If genes did not mean destiny, could I turn things around? Another diet morphed into fundamental and lasting changes through many small adjustments. Gradually my markers for illness improved. At the same time my kids increased the nutrient-density of their diets and incorporated activity into their busy, hectic lives.
Maybe this is epigenetics in action: Small adjustments reprogram our genetic code to yield long-lasting changes, and the traits are passed from one generation to the next first through modeling a different way and eventually by changing the genetic code we pass to our offspring.