SSRIs act on serotonin alone; SNRIs add norepinephrine - a chemical tied to energy, alertness, and pain.
Per NIMH, that second action explains the prescribing patterns: SNRIs often get chosen when depression travels with chronic pain, nerve pain, or heavy fatigue, while SSRIs are the usual first start. Shared ground: both treat depression and anxiety, take 4 to 8 weeks to work, cause mild early side effects that fade, and need tapering rather than sudden stopping. The choice is individual chemistry, not better versus worse.
What to do
Common questions
What is the difference between an SSRI and an SNRI?
Both are first-line antidepressants, and the difference is one neurotransmitter. Per NIMH, SSRIs - selective serotonin reuptake inhibitors like sertraline and escitalopram - raise available serotonin; SNRIs - serotonin-norepinephrine reuptake inhibitors like venlafaxine and duloxetine - raise serotonin plus norepinephrine, a second chemical tied to energy, alertness, and pain signaling. That second action explains the practical prescribing patterns: SNRIs often get chosen when depression travels with chronic pain, nerve pain, or heavy fatigue - duloxetine carries specific pain approvals - while SSRIs are the usual first start for their slightly gentler side-effect profile. Shared ground: both treat depression and anxiety disorders, both take 4 to 8 weeks to work, both commonly cause mild early side effects like upset stomach or headache that fade, and both need tapering, never sudden stopping. The choice between them is individual chemistry and history, not better versus worse - many people try more than one before landing. Pymander, a free AI doctor available 24/7 by text, can help you prepare questions for the prescriber.