Obsessive-Compulsive Disorder in Adulthood: Etiology, Diagnosis, and Treatment

Obsessive-compulsive disorder (OCD) is common, with a lifetime prevalence of 1.3-4.1%, and it usually markedly impairs the quality of life of those affected. The rationale behind this article is to present an up-to-date review of the etiology, diagnosis, and treatment recommendations of OCD in adults.

This narrative review is based on relevant publications, including the revised German clinical practice guideline on OCD.

Genetic factors are estimated to account for 50% of the variance in OCD; up to 30 independent associated loci have been identified across the genome. Stressful and emotionally traumatic life events are psychological risk factors. OCD is characterized by obsessions and compulsions. The ICD-11 subclassifies OCD by the patient's degree of insight into the disorder ranging from "fair to good" to "poor to absent" insight. It also classifies OCD together with related disorders including body dysmorphic disorder, olfactory reference disorder, hypochondriasis, pathological hoarding, body-focused repetitive behaviors, and Tourette syndrome. Disorder-specific cognitive behavioral therapy, with exposure and response prevention, is the first line of treatment with high effect sizes (Hedges' g: 1.13-1.39). Pharmacological therapy primarily involves serotonergic antidepressants (SSRI as first-line and clomipramine as second-line treatment). If necessary, treatment may be augmented with low-dose atypical antipsychotic drugs (aripiprazole or risperidone). For non-responders to psychotherapy and psychopharmacotherapy repetitive transcranial magnetic stimulation or bilateral deep brain stimulation may be considered. Novel treatment approaches and formats are now being clinically studied, including Bergen four-day treatment, Internet-based and virtual therapies, and glutamatergic agents.

Effective evidence-based treatments for OCD are already available, and promising new approaches are being studied. A major challenge remains in making these disorder-specific treatments available to patients with OCD.