Obsessive-compulsive disorder (OCD) is currently recognised as one of the most common psychiatric disorders as well as one of the most disabling of all medical disorders. Obsessive-compulsive related disorders (OCRDs), often comorbid with OCD, include many distinct psychiatric conditions (i.e. some somatoform disorders, eating disorders, impulse control disorders and some neurological conditions) which have overlapping symptoms and compulsive qualities with OCD. Although effective treatments exist, OCD and related disorders are often underdiagnosed and undertreated. Serotonin reuptake inhibitors (SRIs) and cognitive behavioural therapy (CBT) represent the first-line treatment for OCD and related disorders. However, the time and the doses of the medications used in the treatment of OCD and related disorders differ from those recommended in depressive disorders. In addition, remission is not common for patients with OCD and related disorders in clinical practice, and poor responders as well as refractory cases may benefit from different treatment strategies including integrated treatment, pharmacological augmentation and brain stimulation techniques.