Complex sentence: About a third of the variance for generalized anxiety disorder has been attributed to genes, and individuals with a genetic predisposition for GAD are more likely to develop GAD, especially in response to a life stressor.
Split into simpler sentences: About a third of the variance for generalized anxiety disorder has been attributed to genes. Individuals with a genetic predisposition for GAD are more likely to develop GAD, especially in response to a life stressor.