The diathesis-stress model and bipolar disorder

Professor James Potash describes how the diathesis-stress model can be used to understand interactions between genes and the environment. He refers specifically to bipolar disorder.

We know that the heritability of bipolar disorder is something on the order of seventy percent; the heritability of major depression is something on the order of forty percent. So it’s clear that a substantial proportion of the risk for these mood disorders is not genetic and it does seem quite plausible that there would be an interaction between genetic susceptibility and stress leading to mood disorders. People have thought that stressful life events have played a role in triggering mood disorders for a long, long time and in fact there are a number of large studies that do show that stressful life events precede the onset of depressions. So it would a certain amount of sense that some of the genes involved in mood disorders would be genes that play a role in the stress response. One of them is called FKBP5, which is a co-chaperone of the glucocorticoid receptor, which is the receptor for the stress hormone cortisol, and there is a fair amount of evidence including some from our group that that gene is involved in bipolar disorder and depression risk.