• depression;
  • obsessive-compulsive disorder;
  • posttraumatic stress disorder;
  • mediation;
  • comorbidity


Previous findings suggested a unique role that depression symptoms might play in the comorbid relationship between obsessive-compulsive disorder (OCD) and posttraumatic stress disorder (PTSD). However, the nature of this role remains unclear. Thus, the current study examined ways in which OCD and PTSD symptoms vary as a function of depression, as well as the mediating role of depression in the OCD-PTSD relationship, in 104 individuals seeking treatment for refractory OCD. Findings revealed that depressed individuals in the treatment-refractory OCD sample report higher levels of overall obsessing and greater severity of PTSD. In addition, depression appeared to mediate the relation between OCD and PTSD. Implications of findings are discussed. © 2011 Wiley Periodicals, Inc. J Clin Psychol 67:1–5, 2011.