Considerations for the treatment of obsessive-compulsive disorder in patients who have comorbid major depression

ABSTRACTIntroduction Obsessive-compulsive disorder (OCD) is a debilitating psychiatric disorder that affects a significant number of individuals worldwide. Major depressive disorder (MDD) is among the most common comorbidities reported in people with OCD. The emergence of MDD in individuals with OCD can be attributed to the increased severity of OCD symptoms and their profound impact on daily functioning. Depressive symptoms can also modify the course of OCD.Areas covered In this review, the authors explore potential shared neurobiological mechanisms that may underlie both OCD and MDD, such as disturbed sleep patterns, immunological dysregulations, and neuroendocrine changes. Furthermore, they address the challenges clinicians face when managing comorbid OCD and MDD. The authors also discuss a range of treatment options for OCD associated with MDD, including augmentation strategies for serotonin reuptake inhibitors (e.g. aripiprazole), psychotherapy (especially CBT/EPR), transcranial magnetic stimulation (TMS), electroconvulsive therapy (ECT), and deep brain stimulation (DBS).Expert opinion Although there is no 'rule of thumb' or universally acceptable strategy in the treatment of OCD comorbid with MDD, many clinicians, including the authors, tend to adopt a unique transdiagnostic approach to the treatment of OCD and related disorders, focusing on strategies known to be effective across diagnoses. Nevertheless, the existing 'cisdiagnostic approaches' still retain importance, i.e. specific therapeutic strategies tailored for more severe forms of individual disorders.KEYWORDS: Deep brain stimulationdepressionelectroconvulsive therapymajor depressive disorderobsessive-compulsive disorderpharmacotherapypsychotherapytranscranial magnetic stimulation Article highlights Approximately 65% of OCD patients develop depression.The reason for this high comorbidity rate remains uncertain, as it could be attributed to either the burden of obsessive-compulsive symptoms or shared neurobiological mechanisms underlying both disorders.Some options, like pharmacotherapy (SSRIs), CBT, TMS, and DBS, may be effective for both disorders. The efficacy of ECT is unclear.In order to effectively manage the simultaneous occurrence of OCD and depression, we propose a transdiagnostic approach to treatment.Clinicians should not be naïve to ignore existing 'cisdiagnostic' approaches, i.e. the specific tailored strategies developed for treatment-refractory and/or more severe neuropsychiatric syndromes.Declaration of interestThe authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.Reviewer disclosuresPeer reviewers on this manuscript have no relevant financial or other relationships to disclose.Additional informationFundingL Fontenelle is supported by the Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ; grant # CNE E-26/200.950/2021, Rio de Janeiro, RJ, Brazil), and intramural grants from D'Or Institute for Research and Education (IDOR, Rio de Janeiro, RJ, Brazil).