Posts Tagged mood
By Jamie Eske, Reviewed by Heidi Moawad, MD
Dopamine and serotonin are chemical messengers, or neurotransmitters, that help regulate many bodily functions. They have roles in sleep and memory, as well as metabolism and emotional well-being.
People sometimes refer to dopamine and serotonin as the “happy hormones” due to the roles they play in regulating mood and emotion.
Dopamine and serotonin are involved in similar bodily processes, but they operate differently. Imbalances of these chemicals can cause different medical conditions that require different treatments.
In this article, we look at the differences between dopamine and serotonin, their relationship, and their links with medical conditions and overall health.
What is dopamine?
Neurons in the brain release dopamine, which carries signals between neurons.
The body uses dopamine to create chemicals called norepinephrine and epinephrine.
Dopamine plays an integral role in the reward system, a group of brain processes that control motivation, desire, and cravings.
Dopamine levels also influence the following bodily functions:
- blood flow
- urine output
What is serotonin?
Serotonin is another neurotransmitter present in the brain.
However, more than 90% of the body’s total serotonin resides in the enterochromaffin cells in the gut, where it helps regulate the movement of the digestive system.
In addition to aiding digestion, serotonin is involved in regulating:
- the sleep-wake cycle
- mood and emotions
- metabolism and appetite
- cognition and concentration
- hormonal activity
- body temperature
- blood clotting
Differences between dopamine and serotonin
Although both dopamine and serotonin relay messages between neurons and affect mood and concentration, they have some other distinct functions.
Dopamine, for example, relays signals between neurons that control body movements and coordination.
This neurotransmitter also plays a role in the brain’s pleasure and reward center, and it drives many behaviors. Eating certain foods, taking illicit drugs, and engaging in behaviors such as gambling can all cause dopamine levels in the brain to spike.
Higher levels of dopamine can lead to feelings of euphoria, bliss, and enhanced motivation and concentration. Therefore, exposure to substances and activities that increase dopamine can become addictive to some people.
Like dopamine, serotonin can also influence people’s moods and emotions, but it helps regulate digestive functions such as appetite, metabolism, and gut motility.
The relationship between dopamine and serotonin
They interact with and affect each other to maintain a careful chemical balance within the body. There are strong links between the serotonin and dopamine systems, both structurally and in function.
In some cases, serotonin appears to inhibit dopamine production, which means that low levels of serotonin can lead to an overproduction of dopamine. This may lead to impulsive behavior, due to the role that dopamine plays in reward seeking behavior.
Serotonin inhibits impulsive behavior, while dopamine enhances impulsivity.
Dopamine and serotonin have opposite effects on appetite; whereas serotonin suppresses it, low levels of dopamine can stimulate hunger.
Which conditions have links to dopamine and serotonin?
Having abnormal levels of either dopamine or serotonin can lead to several different medical conditions.
Both neurotransmitters can affect mood disorders such as depression. Imbalances can also result in distinct conditions that affect different bodily functions.
In the sections below, we cover these conditions in more detail:
Having too much or too little dopamine can impair communication between neurons and lead to the development of physical and psychological health conditions.
Dopamine deficiency may play a significant role in the following conditions and symptoms:
Dopamine also plays a role in motivation and reward driven behaviors.
Although dopamine alone may not directly cause depression, having low levels of dopamine may cause specific symptoms associated with depression.
These symptoms can include:
- lack of motivation
- difficulty concentrating
- feelings of hopelessness and helplessness
- loss of interest in previously enjoyable activities
The SLC6A3 gene provides instructions for creating the dopamine transporter protein. This protein transports dopamine molecules across neuron membranes.
A medical condition known as dopamine transporter deficiency syndrome, or infantile parkinsonism-dystonia, occurs when mutations in the SLC6A3 gene affect how the dopamine transporter proteins function.
Dopamine transporter deficiency syndrome disrupts dopamine signaling, which impacts the body’s ability to regulate movement.
For this reason, dopamine transporter deficiency syndrome produces symptoms similar to those of Parkinson’s disease, including:
- tremors, spasms, and cramps in the muscles
- difficulty eating, swallowing, speaking, and moving
- impaired coordination and dexterity
- involuntary or abnormal eye movements
- decreased facial expression, or hypomimia
- difficulty sleeping
- frequent pneumonia infections
- digestive problems, such as acid reflux and constipation
Similar to dopamine, researchers have linked abnormal levels of serotonin with several medical conditions, especially mood disorders such as depression and anxiety.
Contrary to popular belief, it appears that low serotonin does not necessarily cause depression. Multiple factors beyond biochemistry contribute to depression, such as:
- genetics and family history
- lifestyle and stress levels
- additional medical conditions
That said, having low serotonin levels may increase a person’s risk of developing depression. Serotonin medications — such as selective serotonin reuptake inhibitors (SSRIs), which increase the availability of serotonin in the brain — may also help treat depression.
SSRI medications include:
- fluoxetine (Prozac)
- sertraline (Zoloft)
- escitalopram (Lexapro)
- paroxetine (Paxil)
- citalopram (Celexa)
On the other hand, having too much serotonin can lead to a potentially life threatening medical condition called serotonin syndrome.
Serotonin syndrome, or serotonin toxicity, can occur after taking too much of a serotonergic medication or taking multiple serotonergic medications at the same time.
The Food and Drug Administration (FDA) provided a list of serotonergic medications in 2016. Aside from SSRIs, some of these include:
- serotonin and norepinephrine reuptake inhibitors (SNRIs), such as venlafaxine (Effexor)
- tricyclic antidepressants (TCAs), such as desipramine (Norpramin) and imipramine (Tofranil)
- certain migraine medications, including almotriptan (Axert) and rizatriptan (Maxalt)
According to the FDA, opioid pain relievers can interact with serotonergic medications, which can lead to a buildup of serotonin or enhance its effects in the brain.
The neurotransmitters dopamine and serotonin regulate similar bodily functions but produce different effects.
Dopamine regulates mood and muscle movement and plays a vital role in the brain’s pleasure and reward systems.
Unlike dopamine, the body stores the majority of serotonin in the gut, instead of in the brain. Serotonin helps regulate mood, body temperature, and appetite.
Having too much or too little of either neurotransmitter can cause psychological and physical symptoms.
Deficiency of monoamines, such as dopamine, epinephrine, and serotonin, is the most widely accepted theory explaining mood disorders. Among these neuromediators, serotonin deficiency is considered as most significant in relation to anxiety and depression. This theory has been proven by the effectiveness of drugs that help to increase monoamines levels in the brain, although research in this direction has been hampered by the limitations of present-day technology in measuring the levels of specific monoamines and their properties. However, studies do indicate that their deficiency plays a role in individuals prone to mood swings.
Tryptophan as precursor for serotonin
Tryptophan is one of the essential amino acids. It can’t be produced by our body and has to come through food products rich in proteins. It is required for both anabolic processes and production of various hormones. Tryptophan is a chemical precursor for the synthesis of the neurotransmitter serotonin. This means that the amount of serotonin produced in our body is dependent on the dietary intake of tryptophan. Since serotonin is related to mood regulation, it is entirely possible that tryptophan deficits may have a negative effect on our mood state. On the other hand, its supplementation may be helpful in disorders like anxiety or depression. Multiple investigations seem to support the idea that decreased levels of tryptophan lead to a reduction in serotonin and changes in mood. Some studies have indicated that higher intake of tryptophan may improve social interactions by improving mood and decreasing aggression and dominant behavior.
Serotonin in mood and cognition
Serotonin is important for both mood regulation and regulation of cognitive functions like learning and memory. The effect of monoamine inhibitors called serotonin reuptake inhibitors in various disorders of mood supports this theory. However, it is important to keep in mind that antidepressants are only partially effective in treating mood disorders since monoamine deficits are just one of the factors influencing mood. Most of the serotonin in our body is produced outside the brain, indicating that this compound has a much broader role in our normal physiology. It is possible that many functions of serotonin are still not understood.
Tryptophan depletion and mood regulation
To understand the role of serotonin, and more specifically tryptophan, many tryptophan-depletion studies have been done in recent times. In one simple crossover study, 25 healthy adults were studied for mood changes like anxiety and depression after consuming either a high tryptophan diet or a low tryptophan diet for four days. Tryptophan consumption seems to affect mood even in such a short interval. The study showed that those on a high tryptophan diet had much better mood as compared to those on a low tryptophan diet, although the negative effects of a low tryptophan diet were less pronounced. If such a quick and straightforward analysis can show the difference, it is entirely possible that long-term low tryptophan consumption or depletion may have much graver consequences for mental health.
Tryptophan and gut-brain axis
When we talk about the gut-brain axis we are not just discussing the digestive role of the gut and its effect on overall health, something that has been well known for many years. Our digestive system is also involved in neuro-hormonal signaling, through which it can have an impact on brain functioning. Recently, the influence of gut health on the brain has been the subject of many studies and for good reason. Our gut has more nerve cells than our spine, and it produces many hormones that have various implications for health. Further, it is now well understood that the neural relationship between the gut and brain is dual-sided, and there are more nerve fibers sending information from the gut to the brain rather than from the brain to the gut. Thus, due to the effect of nerves, hormones, and other neurologically active compounds, the gut plays a prominent role in mental wellbeing. Even small changes in the gut could directly affect our behavior. Gut microbiota and their relationship to mood have also recently received lots of attention.
When it comes to tryptophan, the digestive system is not solely involved in its absorption or metabolism. Now it is well-established that serotonin is mostly produced in the gut rather than in the brain, further strengthening the theory of gut-brain interrelation. This theory explains the mood alterations in irritable bowel syndrome (IBS). Further, the development of IBS has been shown to be connected to tryptophan depletion.
The studies show that tryptophan depletion, due to its relationship with serotonin, is undoubtedly one of the most essential elements to consider when analyzing altered mood and cognition. Low serotonin could generally cause a state of lowered mood, impaired cognition, poor working memory, and lower reasoning. Conversely, high tryptophan supplementation could have a positive effect on mood, memory, energy level, and emotional processing.
Low dietary consumption of tryptophan could be one of the elements leading to chronic conditions like depression and anxiety. Bowel conditions like IBS that disturb tryptophan metabolism and alter serotonin levels may also modify our behavior and feelings.
The search for effective therapeutic approaches to the treatment of mood disorders, anxiety, and depression has gained lots of attention in the last few decades. Understanding the role of tryptophan may open up new possibilities for managing mood and cognition problems. It is quite possible that a high tryptophan diet may not only help to prevent mood disorders but also increase the effectiveness of existing drug therapies.
Delgado, P. L. (2000) Depression: the case for a monoamine deficiency. The Journal of Clinical Psychiatry, 61 Suppl 6, 7–11. PMID: 10775018
Jenkins, T. A., Nguyen, J. C. D., Polglaze, K. E., & Bertrand, P. P. (2016) Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis. Nutrients, 8(1). doi: 10.3390/nu8010056
Lindseth, G., Helland, B., & Caspers, J. (2015). The Effects of Dietary Tryptophan on Affective Disorders. Archives of Psychiatric Nursing, 29(2), 102–107. doi: 10.1016/j.apnu.2014.11.008
Young, S. N., & Leyton, M. (2002) The role of serotonin in human mood and social interaction. Insight from altered tryptophan levels. Pharmacology, Biochemistry, and Behavior, 71(4), 857–865. PMID: 11888576
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Personality, once thought to be fundamental and resistant to change, can shift in response to therapy, new research finds.
The study synthesizes data from 207 published research papers that measured personality traits as one outcome of various psychotherapies. Though most of the research was observational rather than experimental, the review, which was published on Jan. 5 in the journal Psychological Bulletin, adds new weight to the idea that personality is not static.
But that doesn’t mean that personality change is easy, warned study researcher Brent Roberts, a social and personality psychologist at the University of Illinois.
“For the people who want to change their spouse tomorrow, which a lot of people want to do, I don’t hold out much hope for them,” Roberts said. However, he continued, “if you’re willing to focus on one aspect of yourself, and you’re willing to go at it systematically, there’s now increased optimism that you can affect change in that domain.” [10 Things You Didn’t Know About You]
Consistency or change?
And much research has suggested that these traits are stable. For example, one 2010 study showed that people’s personalities were relatively stable from first grade to adulthood, and that a first grader’s personality could predict his or her adult behavior, the review said. People who were impulsive as kids were likely to be talkative and expansive in their interests as adults, while those who were more restrained as children grew up to be more insecure and timid.
Studies such as that one have led some researchers to view personality as basically immutable. But other scientists have challenged that notion, including Roberts in his own research. For example, he and his colleagues foundthat people become more conscientious and emotionally stable during young adulthood and midlife. Openness to new experience increases in the teen years and declines in old age.
If personality can change, even late in life, Roberts told Live Science, the natural next question was whether a person could change his or her personality deliberately. Some research analyzed in the review suggested that even surprisingly short-term interventions might do just that.
In 2009, for example, researchers at Northwestern University in Illinois found that antidepressants make people more extraverted and more emotionally stable. And a 2011 study found that a single dose of psilocybin, the hallucinatory compound in “magic mushrooms,” can increase people’s openness to experience for at least 14 months, which is considered a long-term change.
Gold mine of data
When Roberts and his colleagues first became interested in looking at whether interventions can change personality, they expected to find few studies to analyze, because personality psychologists don’t typically focus on altering personality, Roberts said.
“I thought we could do this pretty quick, which, you should never say that as an academic,” Roberts said. [5 Things You Must Know About Sleep]
To his surprise, Roberts said, he found what he called a “gold mine” of data on personality change. It came from an unexpected source: clinical psychology. While personality psychologists had more or less neglected the question of how to change personality, clinical psychologists had been measuring personality change that resulted from therapy and psychiatric medications all along, but almost as an afterthought.
“Most of the literature is [asking], ‘Does this version of cognitive behavioral therapy work better than that version of cognitive behavioral therapy for anxiety?'” Roberts said. “It’s usually something very specific to a clinically motivated agenda … [but] in the process, they measure a bunch of different things.”
Those things included personality. The biggest changes, Roberts and his colleagues found, were in people’s levels of neuroticism. This trait is marked by jealousy, fear, anxiety and other negative emotions. People typically become less neurotic as they age, Roberts said. The new analysis found that three months of psychological treatment could also significantly lower neuroticism, by about half the amount you might expect to see over 30 to 40 years of adulthood.
“One way to look at that is you get half of a life in a three-month period,” Roberts said. “I honestly did not expect to see effect sizes that large.”
Another personality trait, extraversion, also showed significant, though smaller, changes after psychological interventions. The type of therapy used didn’t seem to matter, the researchers reported Jan. 5 in the journal Psychological Bulletin, though psychotherapy was associated with slightly larger changes in personality than drug therapies alone. Hospitalization for psychiatric problems did not result in any personality changes, the researchers found.
Trait vs. state
One key question is whether the changes were representative of a change in fundamental personality traits versus simply a shift in psychological state, or mood, Roberts said. A person’s mood, for example, can affect how he or she responds to questions about his or her personality.
“If you’re in a bad mood and I force you to take a 150-item personality inventory, you might not respond well,” Roberts said.
Complicating matters, few of the studies available were true experiments that randomly assigned patients to treatment and control groups. Those studies that were experimental, however, did show significantly larger effects on personality in the treatment group compared with the control group, the researchers found. And in the observational studies, follow-ups that took place months or years after treatment showed no evidence that people were backsliding: The changes that followed therapy stayed stable, suggesting that these are changes in people’s basic personality traits rather than moment-by-moment moods, the researchers said. [9 DIY Ways to Improve Your Mental Health]
Still, more studies with long follow-up periods need to be done in order to really test the idea that personality can be changed, Roberts said. Ideal research, he said, would include randomly assigning patients to treatment as well as getting outside observers, like friends or family, to rate any personality changes. A perfect study would also follow people for several years after the treatment, Roberts said.
A further question is what is the “magic ingredient” in therapy that ushers in personality change, Roberts said.
“If you can actually affect change in something like neuroticism or conscientiousness,” he said, “you could possibly have pretty interesting consequences for somebody, because personality traits are important.”
Original article on Live Science.