Obsessive–compulsive disorder (OCD) is a common mental and anxiety disorders occurs at all ages, but more common in younger ages with uncontrollable, and affects 1–1.5% of the general population. Many pharmacological therapies and drugs have been reported to diminish OCD symptoms, as well as increase quality of life. So far, several meta-analyses, however, have directly compared such treatment approaches in OCD and treatment-resistant OCD patients. This review evaluated all treatment options for OCD in both children and adolescents, and aimed to found if existing pharmacological therapies work similarly well, taking into account medical comorbidities such as substance use, anxiety, metabolic disorders, and finally, an overview of issues related to safety and monitoring. Our review included data from 16 meta-analyses and 8 practical guidelines involving OCD patients. In adults with OCD, we found that combined therapy shows favorable outcome versus SRI alone and produced better results. In children with OCD greatest incremental treatment gains occur early in SSRI treatment. Finally in treatment-resistant OCD patients antipsychotic augmentation of SRIs can be regarded as an evidence-based measure for pharmacological therapy. The results of this review mostly support the formerly published reviews on the pharmacological management of OCD. Albeit we could confirm that combination/augmentation of SSRIs significantly improved symptoms in treatment-resistant OCD patient than monotherapy. From a clinical perspective, antipsychotics combination/augmentation of SSRIs should be favorably used if there are comorbidities psychosis that represents a frequent comorbidity in OCD, especially the presence of comorbidities is highly associated with treatment-resistance OCD condition.