The biopsychosocial model in psychiatry tells us that psychiatric disorders arise from a combination of biological, psychological, and social factors. But how do causes at these three ‘levels’ interact, and how do we put this insight to use in treating mental illness? Professor Kenneth Kendler addressed these questions in Oxford’s inaugural Loebel Lectures.
In his first lecture (which you can watch here or listen to here), Kendler shared fascinating empirical data to demonstrate the aetiological complexity of psychiatric disorders. He showed that whilst one’s genes can make it more likely that one will suffer certain disorders, the causal pathway does not run directly from genes to the development of a disorder. Rather, causal pathways often—to use Kendler’s expression—‘loop out’ into the environment. For example, having a genetic predisposition to depression makes you more likely to be depressed, but this is because you will be more sensitive than other people to stressful life events that can cause depression. Another example: alcohol dependency does not simply arise from one’s genes, but via one’s genetically-induced tendency to seek out social groups where drinking is encouraged.