Despite the frequent occurrence of depressive symptoms in obsessive-compulsive disorder (OCD), little is known about the reciprocal influence between depressive and obsessive-compulsive symptoms during the course of the disease. The aim of the present study is to investigate the longitudinal relationship between obsessive-compulsive and depressive symptoms in OCD patients.
We used the baseline and 1-year follow-up data of the Netherlands Obsessive Compulsive Disorder Association (NOCDA) study. In 276 patients with a lifetime diagnosis of obsessive-compulsive disorder, depressive and obsessive-compulsive symptoms were assessed at baseline and at one-year follow-up with the Beck Depression Inventory (BDI) and the Yale-Brown Obsessive Compulsive Symptom (Y-BOCS) scale. Relations were investigated using a cross-lagged panel design.
The association between the severity of depressive symptoms at baseline and obsessive-compulsive symptoms at follow-up was significant (β=0.244, p<0.001), while the association between the severity of obsessive-compulsive symptoms at baseline and depressive symptoms at follow-up was not (β=0.097, p=0.060). Replication of the analyses in subgroups with and without current comorbid major depressive disorder (MDD) and subgroups with different sequence of onset (primary versus secondary MDD) revealed the same results.
There may be other factors, which affect both depressive and obsessive-compulsive symptoms that were not assessed in the present study.
The present study demonstrates a relation between depressive symptoms and the course of obsessive-compulsive symptoms in OCD patients, irrespective of a current diagnosis of MDD and the sequence of onset of OCD and MDD.