**Question:** All are used in OCD except:

A. Fluoxetine
B. Clomipramine
C. Risperidone
D. Aripiprazole

**Core Concept:** Obsessive-Compulsive Disorder (OCD) is a psychiatric disorder characterized by recurrent obsessions (unwanted thoughts, ideas, or impulses) and/or compulsions (repetitive behaviors or mental acts done in response to obsessions in order to prevent or reduce distress).

**Why the Correct Answer is Right:**

D. Aripiprazole is a medication primarily used as a dopamine partial agonist and serotonin antagonist (D2 partial agonist and 5-HT2A antagonist) in the treatment of schizophrenia. Although it is effective in managing OCD symptoms in some cases, it is not specifically designed for OCD treatment.

**Why Each Wrong Option is Incorrect:**

A. Fluoxetine (Prozac) is a selective serotonin reuptake inhibitor (SSRI) primarily used in the treatment of major depressive disorder, panic disorder, and social anxiety disorder. Fluoxetine is effective in managing OCD symptoms due to its action on serotonin neurotransmission.

B. Clomipramine (Anafranil) is a tricyclic antidepressant (TCA) that acts as a serotonin, norepinephrine, and dopamine reuptake inhibitor. It is used in the management of depression, anxiety disorders, and OCD. Clomipramine is a more effective option for treating OCD compared to Aripiprazole due to its broader neurotransmitter targeting.

C. Risperidone (Risperdal) is an atypical antipsychotic medication primarily used in the treatment of schizophrenia, bipolar disorder, and autism. Although Risperidone has shown efficacy in managing OCD symptoms, it is not specifically designed for OCD treatment.

**Clinical Pearl:** In clinical practice, understanding the pharmacology of medications is crucial when choosing appropriate treatments for psychiatric disorders. Aripiprazole is effective in managing OCD symptoms but is not specifically designed for OCD treatment, making it less effective compared to medications like Fluoxetine, Clomipramine, and Risperidone, which are specifically targeted at treating OCD due to their selective action on serotonin neurotransmission.