What is the cause of a feeling of depression in human beings ? Name a drug which can be useful in treating this depression .

Explanation

### Step-by-Step Solution:

1. **Understanding Depression**:
- Depression is a mental health disorder characterized by persistent feelings of sadness, loss of interest, and a variety of emotional and physical problems.

2. **Causes of Depression**:
- The causes of depression are complex and can include:
- **Genetic Factors**: A family history of depression can increase the likelihood of experiencing it.
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