The neurotransmitter serotonin is important to feelings of happiness, relaxation and well being. Low levels produce a variety of symptoms, the majority of which can be classified as mood disorders. In fact, serotonin is so important to maintaining an elevated and comfortable mood that physicians treat depression and other related disorders with serotonin-increasing drugs. These help prevent the chemical from being decomposed by the body and increase its lifetime in the brain, elevating mood.
Depression
One of the most well recognized of the disorders produced by low serotonin levels is depression. Bryn Mawr University explains that the neurotransmitter helps the brain communicate to itself that an individual feels happy and content. Low levels of serotonin can be the result of poor diet, neurological disorders or chemical imbalance. While not all cases of depression relate to low serotonin levels, many patients find that pharmaceutical drugs that increase levels of serotonin in the brain help alleviate symptoms. Unfortunately, some find that these mood-elevating effects prevent happy "highs" as much as they prevent depressed "lows."
Anxiety
While serotonin helps promote happiness, it also produces feelings of relaxation. Individuals who tend to crave carbohydrate snacks such as chips or cookies when they're worried are actually increasing serotonin levels and promoting feelings of relaxation and calm. In their book "Biochemistry," Drs. Mary Campbell and Shawn Farrell explain that the body makes serotonin from a component of protein called tryptophan. While carbohydrate snacks don't contain tryptophan, they do signal the body to use existing tryptophan to make serotonin. Individuals with chronically low serotonin levels may have chronic anxiety, social anxiety disorder, or other psychological concerns such as obsessive compulsive disorder.
Insomnia
For some time, researchers have wondered whether low serotonin levels might lead to insomnia. The reverse was well known--people with high levels of serotonin feel quite sleepy. Milk, an old fashioned cure for insomnia, contains protein, which is full of tryptophan and therefore leads to serotonin synthesis. A side effect of drugs that increase brain levels of serotonin, like Paxil and Prozac, is that they can cause sleepiness, especially in new patients just getting used to the drug. Researchers recently found that dysfunctional serotonin transporters in the brain actually do lead to insomnia, notes a 2010 report in the scientific journal, "Sleep." Since transporters help move serotonin around in the brain, faulty transporters might make it look to the brain as though serotonin levels are low, suggesting that low serotonin is, in fact, associated with insomnia.
References
- Bryn Mawr University: Serotonin Effects
- "Biochemistry"; Mary Campbell, Ph.D. and Shawn Farrell, Ph.D.; 2005
- "Sleep"; Association between a serotonin transporter length polymorphism and primary insomnia; M. Deuschle et al; March 2010
