Symptoms and Disorders

Mental illnesses are on the rise, in fact, the World Health Organization (WHO) estimates that depression will be among the second most common diseases by 2030. People suffering from depression almost always show dysfunction of their serotonin balance.

Typical symptoms of depression include a lack of energy, a feeling of hopelessness, negative (even suicidal) thoughts, sleep disturbances and daytime fatigue. Muscle pain, gastrointestinal complaints or headaches are the most common physical side effects.

The factors that contribute to depression are still not fully understood. One thing is certain, however: There is not just “one” cause of depressive moods. Rather, a wide variety of processes in the body are responsible. Recent studies show that an imbalance of various hormones and neurotransmitters, especially serotonin, is often responsible.

In seasonal affective disorder (SAD), which occurs mainly in the fall and winter months, a serotonin deficiency can also be responsible for the symptoms, which include depressed mood, reduced energy levels, anxiety, increased appetite for carbohydrates and sweets and weight gain.

The reason for the reduced serotonin release in cases of SAD: People suffering from winter depression show more activity of the serotonin transporters (SERT) when there is little sunlight. These transporters remove serotonin from the bloodstream or tissue fluid and trap it in the cells, resulting in a deficit of biologically active serotonin, with the aforementioned symptoms as a consequence.

Fibromyalgia syndrome (FMS) is a complex disease characterized by muscle pain, fatigue, fever, insomnia, irritable bowel symptoms and swollen lymph nodes. Those affected often also experience depression, anxiety, cardiovascular disorders and impairment of their sense of balance and cognitive abilities.

Approximately four percent of the population, mainly women, are affected by FMS. The causes of this syndrome have not been adequately researched, although numerous studies are underway to investigate the factors responsible. Among the limited findings, it is believed that the neurotransmitters in the brains of people suffering from FMS do not function as they do in healthy people. FMS patients have also been shown to have low levels of serotonin, particularly in the brain.

Scientists have also found that the gut and its microbiome influence pain perception. One reason could be that there are more serotonin receptors in the gut than in the brain, with nutrition playing an important role. For example, according to various studies, particular caution is required with fructose because of its ability to negatively influence tryptophan uptake, and thus serotonin production.

How do you feel when you have trouble falling asleep for several nights in a row or wake up again and again during the night, and no amount of counting sheep will bring you the sleep you long for? Waking up the next morning is usually particularly difficult, as is concentrating during the day. Food cravings are not uncommon, and your mood is usually not a good one.

Sleep deprivation over a longer period can also have more serious consequences because the risk of diabetes, obesity and cardiovascular diseases increases enormously. A combination of serotonin and melatonin deficiency may be responsible for all these symptoms and the long-term consequences because serotonin is converted into melatonin at night. As it is, these two hormones work together to ensure a healthy sleep-wake cycle.

Studies have also found that serotonin is important for sleep architecture as well as sleep quality and that it supports the transition from one sleep phase into the next. Another research result: Serotonin helps to achieve healthy sleep at the right time, particularly in the case of sleep disorders caused by stress or anxiety.