Neurotransmitter imbalances
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.Sheffler, Z.M., Reddy, V. and Pillarisetty, L.S., 2023. Physiology, neurotransmitters. StatPearls.
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:Huang, Y., 2026. A review of neurophysiological relationships between sleep disorders and depression. Brain, Behavior, & Immunity – Health. Matteo, S., 2024. Neurotransmitter imbalance and mental health: understanding the link between brain chemistry and psychological disorders. Clinical Depression.
- Cognitive issues
- Sleep issues and insomnia
- Lethargy and exhaustion
- Anxiety
- Depression
Several neurotransmitters are thought to be involved, including:
- Serotonin
- Dopamine
- Norepinephrine (also known as noradrenaline)
- GABA (gamma-aminobutyric acid)
- Acetylcholine
- Endorphins
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.Puig, M.V. and Gulledge, A.T., 2011. Serotonin and prefrontal cortex function: neurons, networks, and circuits. Molecular Neurobiology.
Serotonin levels also act as a gatekeeper to other neurotransmitters in our brains.Naoi, M., Wu, Y., Maruyama, W. and Shamoto-Nagai, M., 2025. Phytochemicals modulate biosynthesis and function of serotonin, dopamine, and norepinephrine for treatment of monoamine neurotransmission-related psychiatric diseases. International Journal of Molecular Sciences.
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:Moncrieff, J., Cooper, R.E., Stockmann, T., Amendola, S., Hengartner, M.P. and Horowitz, M.A., 2023. The serotonin theory of depression: a systematic umbrella review of the evidence. Molecular Psychiatry.
- Irritability
- Sleep issues
- Changes in appetite, and (in particular) sugar cravings
- Rage and anger
- Migraines
- Anxiety
- Depression
- Worry
- Rumination
- Second guessing
- Negative self talk
- Phobias
- PMS
- TMJ and jaw pain
- Lack of confidence
- Imposter syndrome
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:Mikkelsen, N., Damkier, P. and Pedersen, S.A., 2023. Serotonin syndrome – a focused review. Basic & Clinical Pharmacology & Toxicology.
- Confusion and agitation
- Exhaustion
- Headaches
- Shivering, sweating, and goosebumps
- Changes in blood pressure, heart rate, and temperature
- Nausea and vomiting
- Diarrhoea
- 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.Ott, T. and Nieder, A. or better: Wu, Z., Wan, S., Yang, H. et al., 2024. Dopamine in the prefrontal cortex plays multiple roles in the executive function of patients with Parkinson’s disease. Neural Regeneration Research.
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.R., Liebowitz, M.R., Abi-Dargham, A., Zea-Ponce, Y., Lin, S.H. and Laruelle, M., 2000. Low dopamine D2 receptor binding potential in social phobia. American Journal of Psychiatry.
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:Costello, H., Yamamori, Y., Reeves, S., Schrag, A.-E., Howard, R. and Roiser, J.P., 2023. Longitudinal decline in striatal dopamine transporter binding in Parkinson’s disease: associations with apathy and anhedonia. Journal of Neurology, Neurosurgery & Psychiatry.
- Irritability
- 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
- Depression
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 11 Aug. 2026].
- Over-stimulation and excessive excitement
- Heightened sensory perception (hearing, seeing, feeling)
- Feelings of suspicion or paranoia
- Hallucinations
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:Jain, R., Chepke, C., Davis, L.L., McIntyre, R.S. and Raskind, M.A., 2024. Dysregulation of noradrenergic activity: its role in conceptualizing and treating major depressive disorder, schizophrenia, agitation in Alzheimer’s disease, and posttraumatic stress disorder. Journal of Clinical Psychiatry.
- Low mood
- Low energy levels
- Increased appetite
- Weight gain
- Fatigue and exhaustion
- Depression
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.Jain, R., Chepke, C., Davis, L.L., McIntyre, R.S. and Raskind, M.A., 2024. Dysregulation of noradrenergic activity: its role in conceptualizing and treating major depressive disorder, schizophrenia, agitation in Alzheimer’s disease, and posttraumatic stress disorder. Journal of Clinical Psychiatry.
High levels of norepinephrine can lead to other symptoms as well, including:Bouras, N.N. and Mack, N.R., 2023. Prefrontal modulation of anxiety through a lens of noradrenergic signaling. Frontiers in Systems Neuroscience.
- Irritability
- Poor concentration and attention
- Sleep issues
- Exhaustion
- 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:Carello-Collar, G., Bellaver, B., Ferreira, P.C.L., Ferrari-Souza, J.P., Ramos, V.G., Therriault, J. et al., 2023. The GABAergic system in Alzheimer’s disease: a systematic review with meta-analysis. Molecular Psychiatry.
- 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
- physical tension (especially in neck, shoulders, and legs)
- cravings to self medicate with alcohol and sugar to relieve stress and anxiety
- gut issues (butterflies, tension)
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:Zhao, Z., Liu, L. and Zhang, X., 2025. Remimazolam-induced paradoxical reaction in a bipolar patient: a case report. Clinical Case Reports.
- 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.Yuet Ruh, D. et al., 2025. Systematic review: effects of cholinergic signaling on cognition in human pharmacological studies. Neuroscience & Biobehavioral Reviews.
Possible effects of low acetylcholine levels
Low acetylcholine levels can be caused by poor diet, or gut issues. Symptoms can include:
- Confusion and disorientation
- Exhaustion
- Irritability
- Headaches
- Dry mouth
- Gut problems
- Nausea and vomitingeng, Y., Jin, H., Xue, Y.-H., Chen, Q., Yao, S.-Y., Du, M.-Q. and Liu, S., 2023. Current and future therapeutic strategies for Alzheimer’s disease: an overview of drug development bottlenecks. Frontiers in Aging Neuroscience.
- Anxiety
- Depression
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.Kim, H. et al., 2015. Interaction of basal forebrain cholinergic neurons with the glucocorticoid system in stress regulation and cognitive impairment. Frontiers in Aging Neuroscience.
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.Shenoy, S.S. and Lui, F., 2023. Biochemistry, endorphin. StatPearls.
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:García-Domínguez, M., 2025. A comprehensive analysis of fibromyalgia and the role of the endogenous opioid system. Biomedicines.
- High levels of stress
- Headaches
- 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
- Addiction
- Anxiety
- Depression
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:Priyadarsini, A., 2024. The impact of exercise on mental health: a narrative review. International Journal of Advances in Medicine.
- Euphoria
- 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 different 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 reduce.Zhang, X. et al., 2023. Cognitive dysfunction in diabetes: abnormal glucose metabolic regulation in the brain. Frontiers in Endocrinology.
Food intolerances, such as gluten-intolerance, can impact neurotransmitters. Mikulska, J., Pietrzak, D., Rękawek, P., Siudaj, K., Walczak-Nowicka, Ł.J. and Herbet, M., 2024. Celiac disease and depressive disorders as nutritional implications related to common factors — a comprehensive review. Behavioural Brain Research.
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. George, M.Y., Abdel Mageed, S.S., Mansour, D.E. and Fawzi, S.F., 2025. The cortisol axis and psychiatric disorders: an updated review. Pharmacological Reports.
Unhealthy lifestyle habits such as poor sleep patterns, insufficient or irregular nutrition, lack of exercise, etc. can also affect neurotransmitter levels. Kunugi, H., 2023. Depression and lifestyle: focusing on nutrition, exercise, and their possible relevance to molecular mechanisms. Psychiatry and Clinical Neurosciences.
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 Kaur, S., Sharma, P., Mayer, M.J., Neuert, S., Narbad, A. and Kaur, S., 2023. Beneficial effects of GABA-producing potential probiotic Limosilactobacillus fermentum L18 of human origin on intestinal permeability and human gut microbiota. Microbial Cell Factories.
- Serotonin
- 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 Moretti, C.H., Grasset, E., Zhu, J., Yang, G., Olofsson, L.E., Khan, M.T., Bergh, P.-O., Oh, J.-H., Lundqvist, A., van Gils, T., Krämer, M., Olsson, L.M., Patel, P., Mitteregger, M., Espinola Monges, D., Dwibedi, C., Krautkramer, K.A., Koopman, N., Henricsson, M., Macpherson, A.J., Schwartz, T., Grompone, G., van Pijkeren, J.-P., Tremaroli, V., Roos, S., Simrén, M. and Bäckhed, F., 2025. Identification of human gut bacteria that produce bioactive serotonin and promote colonic innervation. Cell Reports.
- Tryptophan an essential amino acid is needed for serotonin production in the gut
- Acetylcholine is produced by the gut bacteria Lactobacillus