How antidepressants work is a subject of ongoing research and speculation. The prevailing theory is that they boost chemicals in the brain, especially the neurotransmitters serotonin and neuropinephrine, that make you feel better.
Don't expect a "high"
Antidepressants aren't like narcotics or alcohol. They don't make you high, or cause hangovers. Their effectiveness is gradual and the benefits are subtle.
Roughly 20% to 30% of people experience side effects serious enough to make them stop taking the medication. Minor side effects such as headache, nausea, diarrhea, dizziness, sweating, tremor, and dry mouth usually ease or go away within a few days or weeks.