Healthy narrative writing

Write for your health? Yes, if you write a story you feel better: the “writing cure” research shows that expressive writing improves health. There is an abundance of evidence that professional poets have poorer health outcomes relative to both other writers and to the population at large. The obvious question for a researcher would be: what are the most important differences between poets and narrative writers? Are they differences in education level, in level of intelligence? Is the outcome of the research due to the design of the research?