Comorbid depression and treatment of anxiety disorders, OCD, and PTSD: Diagnosis versus severity

Although anxiety and depression are highly comorbid disorders, it remains unclear whether and how a concurrent depression affects the outcome of anxiety treatment.

Using anonymized routine outcome monitoring (ROM) data of 740 patients having received specialized treatment for an anxiety disorder, OCD, or PTSD, this study investigates whether a comorbid diagnosis of depression and/or self-reported depression severity levels relate to the patients' improvement following anxiety treatment.

The results show that both the patients with and those without comorbid depression had profited similarly from the anxiety, OCD, or PTSD treatment, regardless of whether depression was merely diagnosed prior to treatment or based on self-reported severity (and assuming a smallest effect size of interest of d = 0.35/r = .2). Importantly, the post-treatment reductions in self-reported depressive symptoms were strongly and positively related to the reductions in self-reported anxiety symptoms and disorder-related disability.

Causal inferences cannot be made due to the retrospective cross-sectional design.

The outcomes obtained in a naturalistic patient sample support current treatment guidelines recommending evidence-based treatment for anxiety disorders, OCD, and PTSD in patients with and without a comorbid depression. Future treatment studies are recommended for investigate the (bi)directionality of anxiety and depressive symptoms throughout treatment.