Stress, Pain and Insomnia; Different Conditions or Reflections of the same Problem?

People often report several symptoms and stress, pain and sleep frequently occur alone in combination.  This study follows a large sample of adults over the course of one year to observe these three symptoms.  Thus, we will gain valuable information on how these symptoms overlap.  Moreover, we will also assess how psychological factors influence the development of one or more these problems. A particular goal is to evaluate how the occurrence of one problem influences the subsequent development of an additional problem.  Finally, we study how underlying psychological factors may influence more than one of these problems, that is whether there are mutual (transdiagnostic) factors that drive these problems.