When it comes to psychiatric disorders, genes rarely act alone. Considerable research conducted by the Psychiatric Genomics Consortium (PGC) and other scientists has identified a genetic component to psychiatric disorders, but genes are not the only factors influencing risk. For example, not everyone with a family history of schizophrenia develops schizophrenia, and some people develop schizophrenia even though no one else in their family has ever had the illness. Clearly, other factors are involved. The environment also plays an important role. Scientists involved with the PGC are also deeply interested in understanding ways in which the environment influences our mental health. In fact, advancing our understanding of genetics can help us understand why some individuals are more vulnerable to environmental stressors than others.
For some of the conditions studied by the PGC, the environment is a necessary part of the illness. For example, post-traumatic stress disorder (PTSD) occurs after experiencing or witnessing a traumatic environmental event such as military combat, natural disasters, terrorist incidents, serious accidents, or physical or sexual assault in adulthood or childhood. Some of the key genetic questions become why some individuals develop life-impairing PTSD symptoms after exposure to a traumatic event, whereas others can recover without long-term effects.
For many other of the conditions we study, the environment can trigger or worsen the illness. Depression can be intensified by loss of a loved one, social anxiety disorder can amplify if you are frequently asked to speak in public, an eating disorder can be triggered or made worse by someone teasing you about your body shape or weight. Environmental factors can work hand in hand with genetic factors to define who is at risk.
Environment can also serve as a buffer even to individuals who are at high genetic risk for some psychiatric disorders. Someone who is genetically predisposed to depression might find that being surrounded by highly supportive family and friends can help them recover from a loss without developing a depressive episode. Someone who is genetically at risk for developing a substance use disorder might find that never taking that first drink and being in a substance free relationship protects them from exposures that could ignite an underlying predisposition to alcohol use disorder.
PGC researchers actively engage in science that explores how both genes and environment act and co-act to influence our mental health.