Questions: The medication most often used in the treatment of bipolar disorder is 1) Antibiotics 2) Monoamine oxidase inhibitors (MAOIs) 3) Tricyclics 4) Lithium

The answer is the fourth one: Lithium.

Explanation for each option:

1. Antibiotics: These are used to treat bacterial infections and are not relevant to the treatment of bipolar disorder.

2. Monoamine oxidase inhibitors (MAOIs): These are a class of antidepressants used to treat depression, but they are not the primary medication for bipolar disorder.

3. Tricyclics: These are another class of antidepressants, which can sometimes be used in treating depression associated with bipolar disorder, but they are not the most commonly used medication for bipolar disorder itself.

4. Lithium: This is the most commonly used medication for the treatment of bipolar disorder. It is a mood stabilizer that helps to control the manic and depressive episodes associated with the condition.

In summary, Lithium is the medication most often used in the treatment of bipolar disorder.