Key Takeaways
- Dopamine and serotonin are both neurotransmitters, meaning they are chemical messengers in the brain that communicate via neurons.
- Serotonin is associated with feelings of happiness, focus, and calm, whilst dopamine is associated with feelings of rewards, motivation, and productivity.
- Dopamine and serotonin are considered the ‘happy hormones’ as they increase positive moods and emotions.
- Both dopamine and serotonin also play a role in regulating digestion by suppressing or increasing appetite, depending on the body’s needs.
- Whilst they have similar effects on the brain and body, they work in different ways.
- A lack of either of these chemicals, or both, has been linked with mental health conditions, especially mood disorders, and addiction.
Serotonin and dopamine are neurotransmitters that play vital roles in regulating mood, motivation, and other bodily functions.
Serotonin is often associated with mood regulation, appetite, sleep, and feelings of well-being.
Dopamine, on the other hand, is linked to pleasure, reward, motivation, and movement. While both influence mood and emotion, their specific functions and pathways in the brain differ considerably.
Serotonin Vs. Dopamine
Below are some of the main differences between serotonin and dopamine:
| Serotonin | Dopamine |
|---|---|
| An inhibitory neurotransmitter | An excitatory neurotransmitter |
| Regulate Mood | Regulate Motivation |
| Associated with feelings of happiness, focus, and calm | Associated with feelings of rewards, motivation, and being productive |
| Contributes to sleep and digestion | Important for normal movement and balance |
| Deficiency is linked with sensitivity to pain, aggressiveness, anxiety, and depression. | Deficiency is linked with sensitivity to memory loss, low sex drive, poor digestion, and poor cognition. |
Table: Serotonin vs. dopamine
What is Serotonin?
Serotonin is a neurotransmitter of the monoamine group, which contains amino acids. Serotonin is of interest to psychologists because of its role in mood. It is given the scientific name 5-hydroxytryptamine (5-HT).
This neurotransmitter is essential for feeling happiness, and low serotonin levels are therefore related specifically to mood disorders such as depression.
What does serotonin do?
Serotonin plays a crucial role in regulating mood, with low levels linked to depression. It also influences sleep, appetite, memory, attention, and reward processing.
Produced primarily in the brain stem’s Raphe nuclei, serotonin is projected to various brain regions, including the nucleus accumbens, lobes, cerebellum, and hippocampus.
As an inhibitory neurotransmitter, it balances other neurotransmitters’ excitatory effects.
Interestingly, most serotonin is found outside the brain, in the gastrointestinal tract, where it promotes healthy digestion.
Serotonin imbalances
Serotonin imbalances can have significant effects on mental health and well-being.
Low serotonin levels are associated with:
- Depression
- Anxiety
- Low self-esteem
- Irritability
- Sleep problems
Reduced serotonin binding to receptors has been linked to social anxiety disorder (SAD) and obsessive-compulsive disorder (OCD), particularly intrusive thoughts.
Conversely, excess serotonin, often due to high doses of certain medications, can cause serotonin syndrome, characterized by restlessness, rapid heartbeat, and muscle rigidity.
Schizophrenia, a complex disorder involving abnormal thoughts and perceptions, has also been associated with serotonin deficits.
What is Dopamine?
Dopamine is also a neurotransmitter found in the CNS, which, like serotonin, is a monoamine neurotransmitter, meaning it is derived from amino acids.
Dopamine is both an excitatory and inhibitory neurotransmitter and, therefore, has various effects.
Dopamine is primarily associated with feelings of pleasure, such as the satisfaction someone may feel from achieving a goal. It is also involved in feelings of motivation, sleep, attention, and memory and is important in movement.
What does dopamine do?
Dopamine plays a key role in the brain’s reward system, motivation, and pleasure.
It is highly concentrated in the midbrain, particularly in the ventral tegmental area (VTA) and substantia nigra.
From the VTA, dopamine is transported through the mesolimbic and mesocortical pathways to various brain regions.
The mesolimbic pathway projects to the nucleus accumbens, amygdala, and hippocampus, which are involved in reward processing, emotional responses, and memory formation.
This pathway reinforces pleasurable experiences and motivates individuals to seek out rewarding stimuli.
The mesocortical pathway, on the other hand, projects to the frontal lobes, which are associated with higher cognitive functions, attention, and conscious experience of pleasure.
Dopamine’s role in these pathways highlights its significance in shaping motivated behaviors and decision-making processes.
Dopamine imbalances
Dopamine imbalances can lead to various physical and mental health issues.
Low dopamine levels may cause symptoms such as:
- Fatigue
- Lack of motivation
- Difficulty concentrating
- Reduced pleasure from usually enjoyable activities
These symptoms are often associated with depression and can significantly impact an individual’s quality of life.
On the other hand, excessive dopamine levels have been linked to schizophrenia, particularly the positive symptoms such as hallucinations and delusions. This is thought to be due to overactivity in the mesolimbic and prefrontal dopamine pathways.
Parkinson’s disease, a neurodegenerative disorder affecting movement and coordination, is also associated with dopamine deficits. As the disease progresses, the death of dopamine-producing neurons in the substantia nigra leads to increasingly severe motor symptoms.
Substance use disorders can also disrupt dopamine functioning, leading to a heightened risk of addiction and a decreased ability to experience pleasure from normal activities.
Do Serotonin and Dopamine Work Together?
Although serotonin and dopamine work and function differently, they interact with each other to maintain a chemical balance in the body.
For example, serotonin and dopamine have opposite effects on appetite. Whilst serotonin suppresses it, low levels of dopamine can stimulate hunger.
Studies have shown that serotonin can influence dopamine activity in the brain.
Serotonin neurons connect to and regulate dopamine neurons, suggesting that serotonin has a modulating effect on dopamine function.
This interaction between serotonin and dopamine may help explain some impulsive and aggressive behaviors.
When serotonin levels are low, it may lead to an overactive dopamine system, resulting in increased impulsivity.
Animal studies support this idea, showing that after a fight, rats had lower serotonin levels but higher dopamine levels, linking decreased serotonin activity with increased dopamine activity during aggression.
Summary
Dopamine and serotonin are essential neurotransmitters that produce similar feelings, especially those related to happiness and good moods. They appear to work together to balance out different bodily effects, as well as being able to inhibit each other.
Whilst producing similar feelings, they produce different effects. Dopamine is primarily related to reward and motivation, while serotonin is primarily involved in happiness and mood.
An imbalance of either of these neurotransmitters, either too much or too little, can have detrimental effects on the body, especially when it comes to mental health.
Whilst these neurotransmitters may not be the direct cause of mental health conditions such as depression, they both appear to have some contribution to mental health and our overall happiness.
References
Dunlop, B. W., & Nemeroff, C. B. (2007). The role of dopamine in the pathophysiology of depression. Archives of General Psychiatry, 64 (3), 327-337.
Eske, J. (2019, August 19). Dopamine and serotonin: Brain chemicals explained. Medical News Today. https://www.medicalnewstoday.com/articles/326090
Frick, A., Åhs, F., Engman, J., Jonasson, M., Alaie, I., Björkstrand, J., Frans, Ö., Faria, V., Linnman, C., Appel, L., Wahlsfedt, K., Lubberink, M., Fredrikson, M. & Furmark, T. (2015). Serotonin synthesis and reuptake in social anxiety disorder: a positron emission tomography study. JAMA Psychiatry, 72 (8), 794-802.
Juarez Olguin, H., Calderon Guzman, D., Hernandez Garcia, E., & Barragan Mejia, G. (2016). The role of dopamine and its dysfunction as a consequence of oxidative stress. Oxidative medicine and cellular longevity, 2016.
Lin, S. H., Lee, L. T., & Yang, Y. K. (2014). Serotonin and mental disorders: a concise review on molecular neuroimaging evidence. Clinical Psychopharmacology and Neuroscience, 12 (3), 196.
Seo, D., Patrick, C. J., & Kennealy, P. J. (2008). Role of serotonin and dopamine system interactions in the neurobiology of impulsive aggression and its comorbidity with other clinical disorders. Aggression and Violent Behavior, 13 (5), 383-395.
Vandergriendt, C. (2020, July 16). What the Difference Between Dopamine and Serotonin? Healthline. https://www.healthline.com/health/dopamine-vs-serotonin
Further Reading
- Carhart-Harris, R. L., & Nutt, D. J. (2017). Serotonin and brain function: a tale of two receptors. Journal of Psychopharmacology, 31(9), 1091-1120.
- Harmer, C. J., Duman, R. S., & Cowen, P. J. (2017). How do antidepressants work? New perspectives for refining future treatment approaches. The Lancet Psychiatry, 4(5), 409-418.
- Olivier B. Serotonin: A never-ending story. European Journal of Pharmacology. 2015;753:2-18.
- Cowen, P. J., & Browning, M. (2015). What has serotonin to do with depression?. World Psychiatry, 14(2), 158.
