PTG stands for post-traumatic growth, which is a theory that explains positive psychological change experienced as a result of struggling with highly challenging, highly stressful life circumstances. It was developed by psychologists Richard Tedeschi and Lawrence Calhoun in the mid-1990s. PTG is a part of the positive psychology movement, which intends to lay claim on all capacities of positive mental functioning. Positive psychological changes and outcomes are defined as a part of positive psychology, and PTG is specifically the positive psychological changes post-trauma. The domains of PTG are defined as the different areas of positive psychological changes that are possible post-trauma. Examples of PTG include increased personal strength, greater appreciation for life, spiritual growth, altered belief systems, and motivation to take action to help others in the community.