Antidepressants are prescribed for depressive and bipolar disorders because they appear to affect the amount or functioning of in the brain.

The correct answer is norepinephrine, dopamine and serotonin.

There are several different types of antidepressants; selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MOAs) and many others.

All of these antidepressants have various actions but each of them acts on the reuptake of one of these neurotransmitters. It has been shown that imbalances in the levels of these three neurotransmitters can affect the development of depression and bipolar disorders.

Antidepressants are prescribed for depressive and bipolar disorders because they appear to affect the amount or functioning of serotonin and norepinephrine in the brain.  

Serotonin and norepinephrine reuptake inhibitors (SNRIs) are a class of antidepressant medications that impact neurotransmitters used to communicate between brain cells. More precisely, SNRIs block the reabsorption (reuptake) of the serotonin and norepinephrine in the brain and as a result, the level of these neurotransmitters are increased. That plays a key role in stabilizing mood.