## **Core Concept**
The question tests knowledge of pharmacological properties of drugs used in treating obsessive-compulsive disorder (OCD), specifically their anticholinergic side effects. Anticholinergic effects are associated with blockade of muscarinic acetylcholine receptors. Drugs used for OCD include selective serotonin reuptake inhibitors (SSRIs), clomipramine, and other tricyclic antidepressants.

## **Why the Correct Answer is Right**
Clomipramine, a tricyclic antidepressant (TCA), is known for its strong anticholinergic properties due to its potent blockade of muscarinic receptors. This is a significant side effect profile compared to SSRIs, which generally have fewer anticholinergic effects. Among the TCAs, clomipramine is particularly noted for its high affinity for muscarinic receptors, which contributes to its efficacy in treating OCD but also increases the risk of anticholinergic side effects like dry mouth, constipation, and urinary retention.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because SSRIs, which this option likely represents, have minimal anticholinergic effects compared to tricyclic antidepressants like clomipramine.
- **Option B:** Without specific details, it's hard to assess, but if this option represents another TCA with less anticholinergic potency than clomipramine, it would be incorrect.
- **Option D:** Similarly, without specifics, if this option suggests another class or drug with less anticholinergic effect than clomipramine, it would be incorrect.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while clomipramine is effective for OCD and has a high potency for serotonin reuptake inhibition, its significant anticholinergic side effects can limit its tolerability. Clinicians often start with a low dose and titrate carefully. A classic clinical correlation is that patients on clomipramine may experience dry mouth, blurred vision, constipation, and urinary hesitancy.

## **Correct Answer:** C. Clomipramine