You have it backward I believe. When serotonin is lower, people have more risk to experience depression.
Hydroxyzine decreases serotonin levels as it a serotonin antagonist.
Ecstasy is mostly know for increasing Serotonin levels in the synapse which it does the most. It also increases levels of dopamine, monoamine, and norepinephrine. Serotonin is associated with your mood/emotions, sleep and appetite. Antidepressant drugs ussually target and increase serotonin levels as people who are depressed have low serotonin levels. This is why ecstasy makes you happy and loving when you take it. Dopamine is what allows us to expierence pleasure or pain, This is why it is sometimes called the reward center of our brain. Low dopamine levels lead to addiction. As far as I know monomine and norpinephrine are closely related to serotonin and are also related to your mood and depression.
decrese
it messes with the serotonin in your brain
There still exist no known norms for serotonin levels, as these vary widely among individuals.
mania
yes
boo
Personally I don't think it is possible to detect the levels of all neurotransmitters, because they are constantly being altered , except on a depressed person in which serotonin normal level drops to a lower one. But there is no needing to determine its level because a psychiatrist can tell when a person is depressed.
If you are depressed, it makes you feel normal again, but it takes 3-5 weeks to kick in.
When you feel ur healthy and no problems are troubling you. Or you can go to ur doctor and take a blood test to check ur levels. Otherwise if u had low levels u would feel depressed all the time, and if u have higher levels u would feel agitations, muscle jerks, u will sweat alot.
Serum serotonin levels can be obtained (as ordered by a physician or nurse practitioner or physician assistant). However, serum serotonin levels do not possess much utililty since they vary widely - some people having low levels despite being on significant doses of setonergic medications, and other people have high levels despite being on very low doses.