Which neurotransmitter has been most closely linked to mood regulation?

Serotonin is often referred to as the "feel-good" neurotransmitter and plays a crucial role in mood regulation. It is involved in managing emotions and impacting feelings of happiness and well-being. Low levels of serotonin have been associated with mood disorders such as depression and anxiety. This connection is one reason why many antidepressant medications, specifically selective serotonin reuptake inhibitors (SSRIs), target the serotonin system to help alleviate symptoms of depression.

While dopamine is also involved in mood and motivation, its primary role is more closely related to reward and pleasure, rather than direct mood regulation. Norepinephrine is associated with alertness and arousal, playing a significant role in the body's fight-or-flight response, which can also influence mood but is not as directly linked to emotional regulation as serotonin. GABA, on the other hand, serves as a major inhibitory neurotransmitter in the brain that helps to calm neural activity and reduce anxiety, but it does not play a primary role in regulating mood in the same way that serotonin does. Therefore, serotonin’s predominant involvement in mood stabilization and overall emotional balance solidifies its importance in mood regulation.