Serotonin is a neurotransmitter, which is a chemical messenger in the brain and nervous system that helps to regulate various physiological functions such as mood, appetite, sleep, and social behavior. It is also known as 5-hydroxytryptamine (5-HT) due to its chemical structure.
Serotonin is synthesized from the amino acid tryptophan in the brain and is primarily found in the gastrointestinal tract, blood platelets, and central nervous system. It is involved in the regulation of many physiological processes, including mood, anxiety, appetite, and sleep.
Abnormal levels of serotonin have been linked to various mood disorders, such as depression, anxiety, and bipolar disorder. Several medications, such as selective serotonin reuptake inhibitors (SSRIs), work by increasing the levels of serotonin in the brain, and are used to treat these conditions.