The Relationship Between Serotonin and Mental Illness

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The Relationship Between Serotonin and Mental Illness

The relationship between serotonin and mental illness has long been examined to develop the most effective forms of care for people with disorders like depression and anxiety. Way back in history, many cultures believed that mental illness was the result of demon possession or a punishment for sin. Nowadays, following centuries of research, we know that mental illness is rooted in both physical and mental changes. Follow along with our Lake Worth drug rehab as we look into the role of serotonin in mental health disorders.

What Is Serotonin?

Serotonin is a chemical that nerve cells produce to communicate with each other. Serotonin is mostly found in the digestive system, although it can also be found throughout the central nervous system and blood platelets.

Serotonin impacts every part of your body, from your emotions to your motor skills. As a natural mood stabilizer, food is one of the most common natural remedies for anxiety relief, and many people will eat certain things or take supplements to increase their serotonin levels. It’s the chemical in the body that plays a major role in sleeping, eating, and digesting. Serotonin also plays a role in:

  • Bowel movements
  • Mood
  • Nausea
  • Sleep
  • Blood clotting
  • Bone health
  • Sexual function

Serotonin is made from the essential amino acid tryptophan that must enter your body through your diet. It’s commonly found in foods like nuts, cheese, and red meat. Tryptophan deficiency can lead to lower serotonin levels, which can lead to behavioral changes and mental illness.

Serotonin Effects on Behavior

While there’s still much to learn about serotonin’s direct impact on mental health and behavior, certain effects are confirmed. Defects in serotonin receptors (5-HT 1A) are known to cause increased anxiety. Additionally, the decrease in serotonin levels generated by the enzyme monoamine oxidase A is linked to violent behavior and antisocial personality disorder.

Increased serotonin levels, caused by the decreased activity in the enzyme monoamine oxidase A, are associated with a higher risk of violent behavior and aggression. Abnormalities in serotonin levels are also red flags for violent behavior and antisocial personality disorder. High levels of serotonin, followed by decreased activity of the monoamine oxidase A enzyme, seem to increase the risk of violent behavior and aggression in adulthood.

In addition to behavior, serotonin also impacts:1

  • Cardiovascular regulation
  • Respiration
  • Body temperature regulation
  • Sleep-wake cycle
  • Appetite
  • Aggression
  • Sexual behavior
  • Pain sensitivity
  • Learning

Does Low Serotonin Cause Anxiety and Depression?

Serotonin is considered the “happy chemical” because it appears to play a role in regulating mood, and low serotonin and mental health disorders like depression and anxiety have been linked. Despite the link between low serotonin and depression, however, it’s unclear whether low serotonin causes depression or depression causes low serotonin.

But what is certain is that there is a link between serotonin and mental illness. One study found that aggressive individuals have higher rates of mental illness and both types of individuals showed low serotonin levels.2 Another 2016 animal study examined mice lacking serotonin autoreceptors that inhibited serotonin secretion in the body.

Without these autoreceptors, the mice showed higher levels of serotonin in their brains, and researchers found these mice showed fewer signs of anxiety and depressive behaviors.3 Although more studies need to be done to clear up the “chicken or the egg” question concerning serotonin and mental illness, it is believed that low serotonin can cause anxiety and depression, particularly when one type of serotonin receptor (5-HT 1A) is impacted.

What Are Normal Serotonin Levels?

You can find out what your serotonin levels are by taking a serotonin blood test. However, this test is usually taken when someone is suspected of having carcinoid syndrome. Carcinoid syndrome is a group of symptoms associated with carcinoid tumors. These tumors are usually found in the small intestine, colon, appendix, and bronchial tubes in the lungs.

However, you can find out what your serotonin levels are by asking your healthcare provider for a blood test. Normal levels of serotonin range from 50 to 200 ng/mL. These may vary slightly depending on the lab and measurements. Always meet with your physician to discuss your results, how they may contribute to certain symptoms (if you’ve experienced any,) and how to improve your levels.

Help for Depression and Anxiety

Serotonin affects every part of your body. It’s responsible for many important functions that we rely on daily. If your serotonin levels aren’t balanced, you’re more likely to experience trouble with your mental, physical, and emotional health. Sometimes, serotonin imbalance can mean something more serious.

As more people work from home and lifestyles are adjusted, you might find yourself struggling with your mental health. If you or someone you care about can relate, our Lake Worth mental health services can help. We offer anxiety and depression treatment, among other programs to help clients understand what triggers their symptoms and how to best manage them.


For more information about our mental health services, call Behavioral Health of the Palm Beaches today at 561-220-3981.



  1. Biological Psychiatry Journal – The Spectrum of Behaviors Influenced by Serotonin
  2. NCBI – Serotonin Dysfunction, Aggressive Behavior, and Mental Illness: Exploring the Link Using a Dimensional Approach
  3. NIH – A Lack of Serotonin 1B Autoreceptors Results in Decreased Anxiety and Depression-Related Behaviors


Related Reading:

Dating With Anxiety: Tips That Can Help

What to Do If Someone Is Suicidal and Refuses Help

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