CASAC Client, Family, and Community Education Practice Test 2026 – Complete Exam Resource

Norepinephrine acts as a key arousal and mood regulator in the brain. It’s released in situations that require heightened alertness and quick responses, ramping up attention, energy, and readiness to act. This immediate, energizing effect links it closely to arousal reactions and mood states, helping you feel wakeful and emotionally tuned to what's happening around you.

GABA, by contrast, is the primary inhibitory neurotransmitter that dampens neural activity, promoting calm and reducing anxiety rather than driving arousal. Dopamine is central to reward, motivation, and movement, so while it can influence motivation and peak performance, its main role isn’t general arousal or mood regulation in the broad sense. Serotonin influences mood and other functions like sleep and appetite, but the rapid, vigilant arousal and mood shifts are most directly tied to norepinephrine.