Neurotransmitters are chemical messengers, which transmit information from our nerve cells to our muscles, organs, or other nerve cells. They play a key role in relaying information around our bodies, regulating our behaviour, and modulating our moods.MedicineNet. (2016). ‘Neurotransmitter’. [online] Available at: http://www.medicinenet.com/script/main/art.asp?articlekey=9973 [accessed 26 Oct. 2017].
The levels of neurotransmitters in our bodies are constantly going up and down. This is natural. But if the levels of certain key neurotransmitters become too low or too high, the resulting imbalance can affect a range of bodily processes, including:
- Our moods
- Our sleep
- Our appetite
- Our memory
- Our attention and focus
- Our anxiety levels
The role of neurotransmitters in mental health issues
The relationship between neurotransmitters and mental health issues is a complex one. But some mental health issues do seem to involve neurotransmitter imbalances. They include:Greenblatt, J. (2011). Breakthrough Depression Solution. Forest Lake, MN: Sunrise River Press, p. 16.Kharrazian, D. (2013). Why Isn’t My Brain Working? Carlsbad, CA: Elephant Press, p. 309.Cass, H., Barnes, K. (2008). 8 Weeks To Vibrant Health. Brevard, NC: Take Charge Books, pp. 124–125.
Several neurotransmitters are thought to be involved, including:
- Norepinephrine (also known as noradrenaline)
- GABA (gamma-aminobutyric acid)
A minority of doctors and scientists reject the connection between neurotransmitters and mental health, and research into the area is ongoing. But there’s already clear evidence for a correlation, at least, between mental health symptoms and neurotransmitter imbalances.
Key neurotransmitters and their effects on mental health
There are many different neurotransmitters, and when they are imbalanced, they can contribute to a wide range of mental health symptoms.
Below are some of our key neurotransmitters, and examples of the effects they can have.
Serotonin is a neurotransmitter that regulates our appetite, our sleep patterns, and in particular our moods.
The frontal lobe is full of receptor sites for serotonin. It’s the control centre of the brain, and it determines our planning, organisation, self-control, and learning. As a result, we need healthy serotonin levels to keep our frontal lobes functioning well.Kharrazian, D. (2013). Why Isn’t My Brain Working? Carlsbad, CA: Elephant Press, pp. 284–285.DesMaisons, K. (1998). Potatoes Not Prozac. New York, NY: Simon & Schuster, p. 229.
Serotonin levels also act as a gatekeeper to other neurotransmitters in our brains.Gottfried, S. (2013). The Hormone Cure. New York, NY: Scribner, p. 151.
Possible effects of low serotonin levels
Low levels of serotonin can be caused by a poor diet, or a lack of natural sunlight.
There is evidence that this can have several effects on our mental health, including:Amen, D. (2013). Unleash The Power Of The Female Brain. New York, NY: Harmony Books, p. 118.Greenblatt, J. (2011). Breakthrough Depression Solution. Forest Lake, MN: Sunrise River Press, p. 16.Gluck, M. and Edgson, V. (2010). It Must Be My Hormones. Camberwell: Penguin Group, p. 50.Kharrazian, D. (2013). Why Isn’t My Brain Working? Carlsbad, CA: Elephant Press, p. 288.
- Sleep issues
- Changes in appetite, and (in particular) sugar cravings
- Rage and anger
Possible effects of high serotonin levels
High levels of serotonin are usually caused by drugs and/or supplements that artificially elevate our serotonin levels.
Too much serotonin can lead to excessive nerve-cell activity, and the following symptoms:Mental Health Daily. (2017). ‘High serotonin levels: symptoms and adverse reactions’. [online] Available at: http://mentalhealthdaily.com/2015/04/04/high-serotonin-levels-symptoms-adverse-reactions/ [accessed 26 Oct. 2017].WebMD. (2017). ‘What is serotonin syndrome?’ [online] Available at: http://www.webmd.com/depression/guide/serotonin-syndrome-causes-symptoms-treatments#1 [accessed 26 Oct. 2017].
- Confusion and agitation
- Shivering, sweating, and goosebumps
- Changes in blood pressure, heart rate, and temperature
- Nausea and vomiting
- Loss of muscle coordination
Dopamine is a neurotransmitter that plays a major role in reward-motivated behaviour. It’s also associated with our levels of attention and motivation, and our short-term memory.
The frontal lobe is full of receptor sites for dopamine. This is the control centre of the brain, and it determines our planning, organisation, self-control, and learning. As a result, we need healthy dopamine levels to keep our frontal lobes functioning well.Kharrazian, D. (2013). Why Isn’t My Brain Working? Carlsbad, CA: Elephant Press, p. 2.
Research has suggested that dopamine may also be a key factor in social anxiety. Some people who suffer from generalised social phobia have lower levels of dopamine.Schneier, F., Liebowitz, M., Abi-Dargham, A., Zea-Ponce, Y., Lin, S., Laruelle, M. (2000). ‘Low dopamine D(2) receptor binding potential in social phobia’. American Journal of Psychiatry, [online] 157(3), pp. 457–459. Available at: https://www.ncbi.nlm.nih.gov/pubmed/10698826 [accessed 22 Aug. 2017].
Possible effects of low dopamine levels
Low levels of dopamine can be caused by the long-term use of addictive substances, as a result of too much dopamine production over time. They may also be a side-effect of conditions such as Parkinson’s disease.
They can lead to symptoms including:Kharrazian, D. (2013). Why Isn’t My Brain Working? Carlsbad, CA: Elephant Press, p. 331.
- Inability to handle stress
- Inability to feel pleasure and enjoyment
- Lack of self-worth and sociability
- Lack of concern for family and friends
- Poor concentration, attention, and motivation
- Feelings of hopelessness
Possible effects of high dopamine levels
High levels of dopamine can be caused by the use of addictive substances, especially stimulants. They can also be a side-effect of irregular sleep-patterns or insomnia.
They can lead to symptoms including:Mental Health Daily. (2017). ‘High dopamine levels: symptoms and adverse reactions’. [online] Available at: http://mentalhealthdaily.com/2015/04/01/high-dopamine-levels-symptoms-adverse-reactions/ [accessed 26 Oct. 2017].
- Over-stimulation and excessive excitement
- Heightened sensory perception (hearing, seeing, feeling)
- Feelings of suspicion or paranoia
Norepinephrine, also known as noradrenaline, is a chemical that controls our bodies’ reaction to stressful situations. When our brains are faced with stress, they signal the adrenal glands to release norepinephrine and other stress hormones like cortisol.
Norepinephrine is important for our emotions, our sleep patterns, and our levels of attention
Possible effects of low norepinephrine levels
Low levels of norepinephrine can lead to symptoms including:Greenblatt, J. (2011). Breakthrough Depression Solution. Forest Lake, MN: Sunrise River Press, p. 16.
- Low mood
- Low energy levels
- Increased appetite
- Weight gain
- Fatigue and exhaustion
Possible effects of high norepinephrine levels
Almost all anxiety disorders involve high levels of norepinephrine. Severe and sudden increases in norepinephrine can be associated with panic attacks. Research has also shown that some people with depression have norepinephrine imbalances.Hughes, J., Watkins, L., Blumenthal, J., Kuhn, C., Sherwood, A. (2004). ‘Depression and anxiety symptoms are related to increased 24-hour urinary norepinephrine excretion among healthy middle-aged women’. Journal of Psychosomatic Research, [online] 57(4), pp. 353–358. Available at: https://www.ncbi.nlm.nih.gov/pubmed/15518669 [accessed 22 Aug. 2017].
High levels of norepinephrine can lead to other symptoms as well, including:St. John, T.M. (2017). ‘High norepinephrine symptoms’. [online] LiveStrong.com. Available at: https://www.livestrong.com/article/138774-high-norepinephrine-symptoms/ [accessed 15 Nov. 2017].
- Poor concentration and attention
- Sleep issues
- Increased heart rate and blood pressure
- Increased rate of breathing (hyperventilation)
- Feelings of anxiety, fear, and dread
GABA is a major inhibitory neurotransmitter. It stops our brains from transmitting other neural signals, and helps us to stay calm, relaxed, and focused.
Possible effects of low GABA levels
Low levels of GABA can be caused by stress, poor diet, or gut issues. Symptoms can include:Kharrazian, D. (2013). Why Isn’t My Brain Working? Carlsbad, CA: Elephant Press, p. 313.Luscher, B., Shen, Q., Sahir, N. (2011). ‘The GABAergic deficit hypothesis of major depressive disorder’. Molecular Psychiatry, [online] 16(4), pp. 383–406. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3412149/ [accessed 22 Aug. 17].
- Lack of focus
- Restless or racing thoughts
- Difficulty ‘switching off’
- Sleep issues
- Feelings of anxiety, panic, or dread, for no apparent reason
- Poor memory, in some cases leading to Alzheimer’s disease
Possible effects of high GABA levels
Excessively high levels of GABA are rare, but they can be caused over time by taking too much of a ‘GABAergic substance’ (a substance that alters GABA levels).
Symptoms can include:Arnulf, I., Konofal, E., Gibson, K.M., Rabier, D., Beauvais, P., Derenne, J.P., Philippe, A. (2005). ‘Effect of genetically caused excess of brain gamma-hydroxybutyric acid and GABA on sleep’. Sleep, [online] 28(4), pp. 418–424. Available at: https://www.ncbi.nlm.nih.gov/pubmed/16171286 [accessed 15 Nov. 2017].Kaye, S. (2017). ‘Side effects of too much GABA’. [online] LiveStrong.com. Available at: https://www.livestrong.com/article/63549-side-effects-much-gaba/ [accessed 15 Nov. 2017].
- Skin problems
- Gut problems (a ‘paradoxical reaction’ where the treatment makes the issue worse)
- Anxiety (another ‘paradoxical reaction’)
Acetylcholine is a neurotransmitter that helps to turn our short-term memory into long-term memory. This takes place in our hippocampus.
Acetylcholine is important for other cognitive functions too, such as learning and attention. It also helps to regulate our heart rate and gut function.De Jaeger, X., Cammarota, M., Prado, M., Izquierdo, I., Prado V., Pereira, G. (2013). ‘Decreased acetylcholine release delays the consolidation of object recognition memory’. Behavioural Brain Research, [online] 238, pp. 62–68. Available at: https://www.ncbi.nlm.nih.gov/pubmed/23089649 [accessed 22 Aug. 17].Nnama, H. (2017). ‘The benefits of acetylcholine’. [online] LiveStrong.com. Available at: https://www.livestrong.com/article/439478-the-benefits-of-acetylcholine/ [accessed 15 Nov. 2017].
Possible effects of low acetylcholine levels
Low acetylcholine levels can be caused by poor diet, or gut issues. Symptoms can include:
- Confusion and disorientation
- Dry mouth
- Gut problems
- Nausea and vomiting
- Memory problems, in some cases leading to Alzheimer’s disease Francis, P. T. (2005). The interplay of neurotransmitters in Alzheimer’s disease. [online] CNS Spectrums, 10 (11 Suppl. 18), pp. 6-9. Available at: https://www.ncbi.nlm.nih.gov/pubmed/16273023 [accessed 17 Oct. 2017].
Possible effects of high acetylcholine levels
Excessively high levels of acetylcholine are rare, and often produce no symptoms before our bodies correct the imbalance.
But if we do experience symptoms, they can look very similar to the symptoms of low acetylcholine levels, as listed above.
High levels of acetylcholine can also, over time, cause elevated levels of the stress hormone cortisol.Kharrazian, D. (2013). Why Isn’t My Brain Working? Carlsbad, CA: Elephant Press, p. 98.
Endorphins are neurotransmitters produced as a response to certain stimuli, especially pain and stress.
They help block our pain, regulate our emotions, and make us experience pleasure and satisfaction.Greenblatt, J. (2011). Breakthrough Depression Solution. Forest Lake, MN: Sunrise River Press, p. 203.Scheve, T. (2017). ‘What are endorphins?’ [online] How Stuff Works. Available at: http://science.howstuffworks.com/life/endorphins.htm [accessed 26 Oct. 2017].Dutt, S.S. (2015). ‘Endorphins’. [online] Med India. Available at: http://www.medindia.net/patients/patientinfo/endorphins.htm [accessed 26 Oct. 2017].
Possible effects of low endorphin levels
Low endorphin levels can be caused by a poor diet, a lack of vitamins, or by the aftermath of an endorphin ‘high’.
Symptoms can include:Dr. Axe. (2017). ‘What are endorphins? (Plus, hacks to trick your body into manufacturing more of these feel-good chemicals)’. [online] Available at: https://draxe.com/what-are-endorphins/ [accessed 26 Oct. 2017]. Biggers, A. (n.d.). Endorphins: Effects and how to boost them. [online] Medical News Today. Available at: https://www.medicalnewstoday.com/articles/320839.php [Accessed 16 Oct. 2018].
- High levels of stress
- Pain, especially in the neck or back
- Mood swings
- Sleep issues
- ‘Brain fog’
- Lowered pain threshold
- Sensitivity to light
- Changes in appetite, and (in particular) sugar cravings
Possible effects of high endorphin levels
High levels of endorphins are usually triggered as a response to pain and stress. The symptoms are usually temporary but positive, and can include:Alexander, T. (2017). ‘Benefit of endorphins’. [online] LiveStrong.com. Available at: https://www.livestrong.com/article/361767-benefit-of-endorphins/ [accessed 15 Nov. 2017].
- Improved sleep
- Higher levels of self-esteem
- Relief from stress, depression, or anxiety
- Improved cognitive function
Contributors to neurotransmitter imbalances
Imbalanced levels of neurotransmitters can be caused by our lifestyle, diet, genetics, and other factors. See below for more detail on each of these contributing factors.
Each individual is born with the ability to make varying levels of neurotransmitters (and with varying sensitivity to neurotransmitters).
Environmental factors can turn genes on or off, thereby affecting the production and activity of various neurotransmitters.
Lack of key nutrients (vitamins, amino acids, minerals, etc.) due to either poor diet, or poor digestion and absorption can prevent optimal levels of neurotransmitters.
Poor blood sugar control can impact neurotransmitters. If there is too little glucose () in the brain, then the production of our neurotransmitters is reduced http://neuro.hms.harvard.edu/harvard-mahoney-neuroscience-institute/brain-newsletter/and-brain-series/sugar-and-brain
Food intolerances, such as gluten-intolerance, can impact neurotransmitters. Kharrazian, D. (2013). Why Isn’t My Brain Working?. Carlsbad, CA: Elephant Press, pp. 123-146.
Imbalance in key hormones (sex hormones, stress hormones, thyroid hormone, etc.) can cause imbalances in neurotransmitters.
For instance, low estrogen can lead to low serotonin; low progesterone can lead to low GABA; etc.
Difficult personal circumstances and psychological trauma (death, divorce, abuse, displacement, etc.), can lead to chronic stress, which in turn can affect neurotransmitters. Chronically high cortisol for instance can cause low serotonin and low GABA. http://bjp.rcpsych.org/content/180/2/168?ijkey=876057fb11e4a48089c29ff6ab1c2d22b7430a0d&keytype2=tf_ipsecsha; https://www.webmd.com/depression/features/stress-depression#1; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3889685/
Unhealthy lifestyle habits such as poor sleep patterns, insufficient or irregular nutrition, lack of exercise, etc. can also affect neurotransmitter levels. Longordo F, Kopp C, Luthi A, (2009) “Consequences of sleep deprivation on neurotransmitter receptor expression and function” European Journal of Neuroscience, 29(9): 1810-9, available at https://www.ncbi.nlm.nih.gov/pubmed/19492440 [accessed February 2018] Wurtman, R J (1994) “Effects of nutrients on neurotransmitter release”, Institute of Medicine (US) Committee on Military Nutrition Research; Mariott BM, editor, Washington (DC): National Academies Press (Us) https://www.ncbi.nlm.nih.gov/books/NBK209058/
Gut issues such as leaky gut and gut dysbiosis can impact the production of neurotransmitters:
- Over 40 neurotransmitters are produced in the gut, including GABA, serotonin, acetylcholine, dopamine and noradrenaline
- Gut bacteria produce many neurotransmitters and neuromodulators
- GABA is produced by the gut bacteria Lactobacillus and Bifidobacterium
- Dopamine is produced by the gut bacteria Bacillus Dinan, T., Stilling, R., Stanton, C. and Cryan, J. (2015). Collective unconscious: How gut microbes shape human behaviour. [online] Journal of Psychiatric Research, 63, pp. 1-9. Available at: http://www.sciencedirect.com/science/article/pii/S0022395615000655 [accessed 23 Aug. 2017].
- The brain and certain cells in the gut called the enterochromaffin cells are the main producers of serotonin
- Enterochromaffin cells are neuro-endocrine cells, occurring in the gut wall
- 95% of serotonin is produced in the gut Hadhazy, A. (2010). Think Twice: How the Gut’s “Second Brain” Influences Mood and Well-Being. [online] Scientific American. Available at: https://www.scientificamerican.com/article/gut-second-brain/# [accessed 23 Aug. 2017].
- Tryptophan an essential amino acid is needed for serotonin production in the gut
- Acetylcholine is produced by the gut bacteria Lactobacillus