What is the Difference Between Serotonin and Dopamine?

Serotonin and Dopamine

Serotonin and dopamine are both neurotransmitters. They are similar brain chemicals, often called happy hormones, but they have differences as well. So what is the difference between serotonin and dopamine?

Below we’ll talk more about what each does separately and also how they’re similar.

What Is Serotonin?

Serotonin is a hormone. The hormone plays a role in stabilizing our mood. Serotonin is also important for promoting feelings of happiness and well-being. Serotonin affects your entire body and health. The hormone allows your nervous system cells to communicate with each other and with your brain cells.

Serotonin helps with eating, sleeping, and digestion. If you have too little, it can lead to depression. If you have too much, it can cause excessive nerve cell activity.

Some of the specific ways your body uses serotonin include:

  • Mood: Serotonin is in your brain, and it may help regulate anxiety, happiness, and overall mood. Low levels are associated with depression. Serotonin levels that are too high can decrease arousal.
  • Bowel function: Serotonin is in your intestines and stomach and helps control bowel function and movements.
  • Sleep: The hormone plays a role in stimulating areas of the brain that control sleep and waking. Whether you’re sleeping or awake depends on which part of the brain is stimulated and which of your serotonin receptors are in use.

When your serotonin levels are normal, you may feel emotionally stable, focused, happy, and calm with optimal cognitive function. 

Low levels of serotonin are associated with:

  • Depression
  • Obsessive-compulsive disorder
  • Suicidal behavior
  • Anxiety
  • Sexual dysfunction
  • Digestive problems
  • Instability in mood
  • Problems concentrating

If you experience any symptoms like those above, you should talk to a mental health care provider. You can receive treatment to correct low serotonin levels.

Serotonin Syndrome

Serotonin syndrome occurs when you take medicines that cause high serotonin levels to accumulate in your body.

Dietary supplements, certain medicines, including selective serotonin reuptake inhibitors (SSRIs), and illegal drugs can contribute to serotonin syndrome.

Symptoms of serotonin syndrome include:

  • Agitation
  • Restlessness
  • Confusion
  • High blood pressure
  • Rapid heart rate
  • Dilated pupils
  • Loss of muscle coordination
  • Twitching muscles
  • Muscle rigidity
  • Sweating
  • Headache
  • Shivering
  • Goosebumps
  • Diarrhea

In severe cases, serotonin syndrome can be life-threatening. Signs of severe serotonin syndrome include fever, seizures, irregular heartbeat, and loss of consciousness.

What is Dopamine?

Dopamine is a neurotransmitter also known as a chemical messenger. The neurotransmitter has a direct effect on our central nervous system.

Sometimes,  you may hear dopamine called the pleasure chemical or neurotransmitter, but it doesn’t actually create feelings of pleasure. 

Instead, what dopamine does is reinforce feelings of pleasure. There’s a connection of sensations of pleasure to particular behaviors, making it a feel-good chemical.

Dopamine is part of the reward center in our brain. When our brains produce dopamine, we feel good. We want to do more of what makes us feel good, increasing dopamine production even more.

Also, part of the fight-or-flight response, when we are experiencing a real or perceived threat, can trigger dopamine release. That release is a way to help your body respond to stress appropriately.

Dopamine affects:

  • Arousal
  • The regulation of some hormones and glands
  • Thoughts and emotions
  • Reinforcement and reward
  • Movement

Dopamine affects how we think, move, behave and remember. We all experience it differently, so determining whether your levels are normal, high, or low can be difficult.

When you have too little dopamine, problems may include:

  • Loss of balance
  • Muscle cramps
  • Low energy
  • Anxiety
  • Mood swings
  • Weight change
  • Low sex drive
  • Constipation
  • Tremors
  • Problems sleeping
  • Hallucinations

If your dopamine is too high, it can cause problems sleeping, stress and anxiety. Too much dopamine can also cause aggression.

Disorders That Affect Dopamine

When you have a dopamine disorder, it can cause problems with neurocognitive function. Dopamine is related to a number of psychological illnesses, including:

  • Parkinson’s: Low dopamine levels can occur in neurodegenerative disorders like Parkinson’s. In this disorder, the nerve cells responsible for the production and release of dopamine are dying off.
  • Attention deficit hyperactivity disorder: Studies show there are dopamine disruptions in people with attention deficit disorder. This chemical imbalance may cause symptoms like impulsivity and inattention. It can be difficult for someone with ADHD to change their behavior because of effects on reward and motivation stemming from dopamine levels.
  • Schizophrenia: This disorder may occur because of changes in dopamine receptors and dopamine signaling pathways. When someone with schizophrenia takes a prescribed antipsychotic drug, it can act as a dopamine antagonist.
  • Substance use disorders: Certain behaviors including drinking or using drugs, can trigger dopamine responses that cause addiction. One reason some people are more likely to develop an addiction or substance use disorder than others could be due to differences in their dopamine circuits.
  • Major depressive disorder: MDD is one of the most common mental health disorders. When a person has a dopamine deficiency, it can cause anhedonia. Anhedonia is the inability to feel pleasure, a key symptom of MDD.
serotonin and dopamine

Dopamine vs. Serotonin

Both dopamine and serotonin are neurotransmitters. Both also affect the same things, but they do so differently. So, does serotonin or dopamine make you happy? Both can, but how they do that can differ from one another.


Both dopamine and serotonin are part of depression. Dopamine system dysfunctions can lead to depression symptoms related to motivation and reward. 

Low serotonin on the other hand doesn’t necessarily cause depression. Serotonin is more likely to play a role in processing emotions, which can affect your mood less directly. 

Other Mental Health Conditions

Dopamine is released when you do anything pleasurable, making some things addictive for certain people. Over time, your dopamine system may react less strongly to a substance or activity that once created a rush. You could then consume more of a substance to try and get the same effects.

While dopamine is linked to substance use disorders, ADHD, and schizophrenia, serotonin is associated more with anxiety disorders, autism spectrum disorder, and bipolar disorder.


Interestingly, we have dopamine and serotonin in our gut. As a result, they play a role in digestion and other related bodily functions. 

For example, researchers think dopamine helps regulate insulin release from your pancreas. Dopamine can also help your small intestine and colon move food through your body.

Your gut contains around 95% of all your body’s serotonin. Your gut can release extra serotonin if you eat something harmful. If you have low serotonin in your gut, it can lead to constipation.

The role of serotonin in overall physical health and mental disorders is important to understand. 


Dopamine activity is associated with being awake. Drugs that raise dopamine levels, like amphetamines, increase alertness. Diseases like Parkinson’s that decrease dopamine production cause drowsiness. The effects on sleep are critical points of difference between dopamine and serotonin. 

Serotonin helps regulate your entire sleep-wake system and circadian rhythm. Serotonin can help you stay asleep, but it can also prevent you from falling asleep in situations you shouldn’t.

Serotonin deficiency can lead to disruptions in sleep patterns. 

Final Thoughts On Serotonin vs. Dopamine

There are some similarities between serotonin and dopamine and several differences. Both are neurotransmitters affecting your mood, brain function, and gut health. They’re both often known as happy chemicals. However, they function in different ways. 

If you have concerns about your serotonin or dopamine levels, we encourage you to contact the Mental Health Center of San Diego by calling (858) 258-9883 to learn more about effective treatment options for imbalances.

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