Depressive symptoms during deep transcranial magnetic stimulation or sham treatment for obsessive-compulsive disorder

Evidence suggests that depressive symptoms tend to improve concurrently with obsessive-compulsive disorder (OCD) symptoms during cognitive behavioral therapy (CBT), despite depression not being the primary target of intervention. Studies examining the temporal or mediational relationships of OCD and depressive symptoms have indicated a bidirectional relationship, as prior levels of OCD symptoms influenced subsequent levels of depression, and vice versa. Deep transcranial magnetic stimulation (dTMS) has recently emerged as a treatment option for OCD. Whether dTMS affects depression symptoms similarly to CBT remains to be examined. The current study employed a random intercept cross-lagged panel model (RI-CLPM) to examine the relationship of OCD and depression symptoms in 94 treatment refractory patients, undergoing dTMS or sham treatment. Both OCD and depression symptoms improved significantly. However, a stable, cross-lagged relationship between the variables was not supported. Changes in one symptom domain could not be used to predict the other. The present study was conducted in a treatment refractory population, meaning the present findings may not generalize to treatment naïve patients or those with less severe OCD symptoms. It is unclear whether the study was sufficiently powered to detect the effects of interest, and this concern also meant that examining the dTMS and sham groups independently was not feasible. When treating OCD with dTMS, depression symptoms appear likely to diminish but should be monitored throughout, and additional interventions applied if needed.