Serotonin, a derivative of an amino acid called tryptophan, is a chemical that interacts with nerve receptors in the brain to influence physical and mental functions such as mood, appetite, sleep cycles and pain regulation. Throughout the body, serotonin causes contractions of involuntary muscles such as those found within blood vessels. Low serotonin levels can affect health in numerous ways.
Sleep Disorders
Dennis T. McGinty Ph.D., of the University of California, Los Angeles, notes that serotonin is viewed as having a relationship to the 'clock neurons' and circadian phase control, factors that affect the body's ability to regulate sleep patterns. McGinty notes that serotonin has been examined for its effect on sleep apnea and dreaming, as well.
Serotonin is transformed within the pineal gland into a hormone called melatonin, which MedlinePlus notes has been determined to be 'likely effective' in treating sleep disorders in children with developmental disabilities, as well as in blind people. Melatonin has been deemed 'possibly effective' in treating sleep related disorders such as jet lag and insomnia.
Depression
Depression, according to Sheri Barke, R.D., of the Student Health and Wellness Center at College of the Canyons in Ca., is often associated with low levels of serotonin. Antidepressant medications, called selective serotonin reuptake inhibitors (SSRIs), function by allowing serotonin to remain active in the brain for a longer period. Serotonin functions as a chemical messenger between neurons in the brain.
Dr. Pedro Delgado, chair of the Department of Psychiatry of University Hospitals of Cleveland, has found that low serotonin levels are only associated with depression in patients who have already had a history of depression. The correlation between depression and serotonin is complex and demands further study.
Anxiety
Serotonin levels and anxiety have been linked by a substantial amount of evidence, according to Hammack Laboratory of Behavioral Neuroscience. Though the precise mechanisms by which serotonin affects anxiety are unknown, SSRIs, which cause an elevation in the levels of serotonin in the central nervous system, are known to reduce anxiety levels when they are taken for prolonged periods. However SSRIs administered in acute cases may temporarily increase anxiety levels.
Eating Disorders
Dr. Bruce Cohen of the University of Virginia Health System explains that serotonin affects an area of the brain called the ventromedial hypothalamus, where it inhibits hunger by inducing feelings of satiety. Cohen notes that this aspect of serotonin implicates it as a possible factor in eating disorders such as bulimia. Low levels of serotonin may occur when your body is undernourished, causing you to crave foods that will increase your tryptophan intake and allow the body to create more serotonin.
References
- University of Virginia Health System: Lecture 18: Eating Disorders
- Hammack Laboratory Research: Research
- Psychiatric News: Depression-Serotonin Link: Many Mysteries Remain
- EurekAlert!: How Does Serotonin Effect Depression
- MedlinePlus: Melatonin
- PubMed: Serotonin and Sleep: Molecular, Functional, and Clinical Aspects
