BACKGROUND: Hyperarousal is a common symptom key to the severity of insomnia-, depression-, anxiety-, posttraumatic stress- and attention deficit/hyperactivity disorders. Hyperarousal however remained a loosely defined construct assessed with different questionnaires in different disorders. Here we addressed the unresolved question whether hyperarousal may be one common transdiagnostic construct or rather has multiple, possibly disorder-specific, dimensions.
