Which of the following is a medication known for treating Obsessive-Compulsive Disorder (OCD)?

Anafranil is known for treating Obsessive-Compulsive Disorder (OCD) as it is the brand name for clomipramine, a tricyclic antidepressant that has shown effectiveness specifically in reducing symptoms of OCD. It works by influencing the levels of serotonin, a neurotransmitter linked to mood and anxiety disorders, thereby alleviating obsessive thoughts and compulsive behaviors associated with the disorder.

The other medications mentioned are primarily prescribed for different indications. Tofranil (imipramine) and Pamelor (nortriptyline) are tricyclic antidepressants mainly used for depression and certain anxiety disorders but lack the specific efficacy for OCD that Anafranil has demonstrated. Silenor (doxepin) is primarily used for treating insomnia and does not have established use in treating OCD. Thus, Anafranil stands out as the effective treatment choice for OCD in this context.