Which neurotransmitter is most closely linked to maintaining mood balance and depression?

• A. Dopamine
• B. Norepinephrine
• C. Serotonin
• D. GABA

Answer: (C)

Mood regulation hinges on several neurotransmitter systems, but the serotonin system is most consistently linked to mood balance and depressive symptoms. Serotonin helps regulate emotional processing, sleep, appetite, and social behavior; when its signaling is disrupted, depressive symptoms often arise. Clinically, many antidepressants (like SSRIs) increase serotonin availability in synapses, which can improve mood for many people, underscoring this link. Dopamine is more about reward and motivation, norepinephrine about arousal and stress response, and GABA about general brain inhibition; while involved in mood and affect, they’re not as directly tied to mood regulation as serotonin. Therefore, serotonin is the neurotransmitter most closely associated with maintaining mood balance and depression.