Pleasure Chemicals – Serotonin

Pleasure Chemicals Series

Serotonin | Dopamine | Oxytocin | GABA | Endorphins

Introduction

There are several different chemicals in the body that help us maintain a positive outlook on life and defend against depression, anxiety, or executive dysfunction. These chemicals include serotonin, dopamine, oxytocin, endorphins, and gamma aminobutyric acid (GABA). If your body is not producing one or more of these chemicals, you may experience symptoms such as a low mood, eating more or less than usual, sleeping more or less than usual, an inability to focus, or a general bad mood (though each chemical has different effects on the body, and most of them create many other changes in the body besides impacting mood).

In this series, we’re going to discuss each chemical in a little more depth, talk about what might happen if you lack it, and ways you might be able to get it back. However, keep in mind that the chemicals we’ll be discussing–neurotransmitters, neuropeptides, and hormones–are not very well understood with our current research, as it’s difficult (and expensive) to study the changes each one puts on the body without the ability to isolate each chemical from the other chemicals in the body. 

Serotonin: The regulating chemical

We’ll start our series with a chemical you may already be familiar with or taking medication for: serotonin. Serotonin is both a hormone and a neurotransmitter–and it will be worth doing a brief definition of these terms before we continue. A neurotransmitter is simply a chemical that sends a message from one part of your body to the other–usually over a very short distance within your body. Hormones like insulin, melatonin, and estrogen also send messages to your body, but these chemicals come from specific hormone-secreting glands and often send their messages over a much longer distance.

Serotonin causes several different effects throughout the body, as evidenced by this chart from an article in the 2009 Annual Review of Medicine:

Studies show that serotonin has a regulating effect on many of the body’s systems. 

A Serotonin “Imbalance”?

You may be most familiar with it from advertisements about antidepressant medications called Selective Serotonin Reuptake Inhibitors (SSRIs) and their claims that depression is caused by a chemical imbalance of serotonin; however, the idea of a chemical imbalance is only a hypothesis and has yet to be definitively proven. The article “The Chemical Imbalance Hypothesis: An Evaluation of the Evidence” explains one problem with the theory:

“…even if the evidence demonstrated that, for example, antidepressants do treat the symptoms of depression in a clinically significant manner, this would not demonstrate that the chemical imbalance hypothesis is correct. Aspirin treats the symptoms of headaches by blocking chemical reactions. This does not mean that aspirin treats the underlying etiology of the headache, such as food allergies or stress.”

SSRIs can be very helpful in mitigating the effects of depression for some people, and we do know that serotonin has a strong relationship with emotional regulation. That said, SSRIs currently have a low success rate when compared with placebo, and many research reviews have examined the high level of bias in published SSRI research. None of this information should be used to dissuade you from trying an SSRI if you are depressed, and you should never stop taking an antidepressant without talking to your doctor, as the withdrawal symptoms can be very disrupting. Instead, the point of mentioning this debate is to highlight that we need more information about serotonin and the medications which impact it.

Getting More Serotonin

Serotonin impacts so many areas of the body in part because it is created in several different parts of the body; the serotonin in our brain, which likely has the strongest impact on our mood, only comprises about 1-2% of our total serotonin, with much more being created in the gut. That said, there is such a thing as the “blood-brain barrier”–a certain lining of the cells in our blood that prohibits most chemicals (hormones, nutrients, and pathogens) from reaching our brain. Serotonin that is produced in the body does not cross the blood-brain barrier–therefore the foods you eat do not directly impact the serotonin in your brain or your emotional status. 

Here are a few things that can help:

• Sleep. One of the systems that serotonin regulates is your circadian rhythm, or your sleep schedule. Getting enough serotonin in your day is essential to building up “sleep pressure” which makes you sleepy and ready for bed at the end of the day.
• Sunlight or artificial light therapy may be one powerful source of serotonin, according to a meta-review of 23 studies on the topic. 
• Exercise can also create serotonin in the brain; its effects are so powerful that some people call it a “cure” for depression. This does not need to be an aerobic exercise if you find those too boring; even a nature walk or yoga can help! Pick any kind of movement you enjoy and are likely to be able to stick with. 
• Meditation. Speaking of yoga–yoga is just one form of meditation, which has implications for serotonin as well as many other pleasure chemicals. 10-20 minutes a day is usually a good target.
• Therapy is certainly known for its ability to benefit your emotional state–but thanks to advances in brain scan technology, we are beginning to measure the direct impact of psychotherapy and positive thoughts on the levels of serotonin, dopamine, and other chemicals in our brains.
• Massages have also been shown to increase serotonin and dopamine, both immediately following treatment and in the long-term. 

Serotonin Syndrome

In addition to the above methods, there are some supplements that claim to increase your level of serotonin. However, combining any supplements together–or, particularly, combining serotonergic supplements while taking an SSRI–can lead to Serotonin Syndrome, a potentially deadly condition that arises from having too much serotonin in your blood. Symptoms can range from anxiety and restlessness to tremors, muscle rigidity, gastrointestinal effects, or trouble with your heart or kidneys.

(It’s also worth noting here that grapefruit can react with dozens of medications, including SSRIs.)

Conclusion

Lacking serotonin has often been associated with depression or other instability of mood, though this correlation is not currently well understood. We need more research into serotonin, SSRIs, and the effect of both on the body. In the meantime, if you are noticing that you lack some regulation or control over your mood (feeling low, angry, or stressed, or having trouble with appetite, sleep, memory, or addiction), you may consider talking to your doctor and/or a therapist.