From The Quarterly, Winter 2011
A key environmental factor contributing to and highly predictive of psychiatric illness is stress. Children with a history of trauma or maltreatment are at enormous lifetime risk for anxiety, depression, PTSD, suicide, substance abuse and other mental health problems.
Many, if not most, psychiatric disorders arise from the interplay of genes and environment. Current research looks at gene and environmental predictors of risk and resiliency. Among the challenges of such research is the fact that most psychiatric disorders involve many different genetic anomalies. Also, individuals vary significantly in their genetic vulnerability. Further, there is a large percentage of patients with co-morbidity – co-existence – of anxiety with depression or other disorders.
Molecular mechanisms have recently been identified that show how gene-environment interaction can affect DNA structure and function. A seminal study a few years ago appeared to show that the serotonin transporter gene, part of the system regulating the neurotransmitter serotonin, could moderate the effects of stress on major depression. The gene has two common forms. S is the short form, and people who have it are believed to be more affected by stress and susceptible to mental illness. L is the lower risk form of the gene. Researchers are also looking at what is called brain-derived neurotrophic factor (BDNF). The BDNF system and the serotonin system interact on multiple levels.
Not surprisingly, maltreated children with the highest-risk genetic profiles tend to show the greatest vulnerability to psychiatric disorders. But as research is revealing, these effects are not necessarily fixed. Studies with animals have shown, for example, that maternal behavior can influence, for better or worse, the brain development of their offspring.
Research is also showing that psychiatric ill effects can be reversed with environmental and pharmacological interventions, the earlier the intervention, the better. For example, social support, especially having an adult in their lives that they can count on, can help to promote resiliency in high-risk children. In pharmacological research, current experiments are testing a range of drugs that influence gene expression and DNA structure toward the goal of individualized treatments to optimize efficacy and minimize side effects.
By: Joan Kaufman, Ph.D.