Name a drug used in mental depression.

Explanation

**Step-by-Step Solution:**

1. **Identify the Condition**: The question asks for a drug used in the treatment of mental depression. Mental depression is a psychological condition that affects mood and behavior.

2. **Understand the Class of Drugs**: There are various classes of drugs used to treat mental depression. One prominent class is tranquilizers, which are designed to help manage anxiety, tension, and depression.

3. **List Examples of Drugs**: Some examples of drugs that are used to treat mental depression include:
- **Phenelzine**: This is a monoamine oxidase inhibitor (MAOI) that helps in controlling depression and hypertension.
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