Serotonin is one of the “feel good” chemicals the body uses to regulate mood. When your serotonin levels are normal, you tend to sleep better, have a good appetite, feel less anxiety and generally feel calm and balanced. When serotonin levels are low, you might feel down and have low energy. After all, your sleep is likely to suffer, and low serotonin and depression have historically been linked.
What Is Serotonin?
Serotonin is one of two hormones generally regarded as mood controls. It works with dopamine, the reward hormone you get for completing a challenging task, to help stabilize your mood. Both of these hormones perform multiple tasks in your body.
Serotonin impacts sleep, blood clotting, digestion, anxiety, mood and other functions. Most of the serotonin in your body is in your digestive tract. Only a small fraction of free serotonin reaches your brain to assist with mood. Serotonin works by carrying messages throughout your body, triggering feelings of tiredness, satiation or happiness. When the hormone reaches its intended recipient inside your body, it’s reabsorbed.
Increasing the amount of serotonin in your bloodstream is one of the most common ways doctors treat depression.
How Scientists Are Questioning the Role of Serotonin in Depression
In the 1960s, low serotonin became the widely accepted cause of depression. If it is, depression is a chemical imbalance treated with medications that either increase your serotonin production or slow the reuptake of the hormone so more of it remains in your bloodstream for longer periods of time. However, a recent umbrella study examining data collected across 17 additional studies calls that assumption into question. Since depression affects an estimated 20% of the population and is linked with poor health outcomes, there is ongoing research into this disease to better understand what’s causing it.
Low serotonin is the most commonly recognized reason for depression, but scientists are exploring other possible explanations.
Selective serotonin reuptake inhibitors, or SSRIs, are among the most commonly prescribed antidepressant medications. You might be familiar with brand names such as:
- Celexa
- Lexapro
- Prozac
- Paxil
- Zoloft
But, if depression isn’t linked to low serotonin, as new studies suggest, how effective are these medications?
Effects SSRI Medication Has on Serotonin
SSRIs are commonly prescribed antidepressant medications because they typically have few side effects, and those side effects tend to be minor.
Serotonin is a messenger chemical that travels through the body and is eventually absorbed by nerve cells. When it’s absorbed, that’s called reuptake. SSRIs interfere with the reuptake process. They block reabsorption, leaving more serotonin in the bloodstream. While the extra serotonin has proved effective for many patients, it’s important to note that too much of the hormone is just as dangerous as too little.
Serotonin syndrome can cause a variety of potentially life-threatening side effects, including:
- Confusion or disorientation
- Tachycardia or a high heart rate
- High blood pressure
- Fevers
- Seizures
- Abnormal heart rhythm
- Passing out
It’s important to talk to your doctor when you notice any of the signs of serotonin syndrome, like nausea, diarrhea or tremors.
Neuroplasticity and Depression
Contrary to the popular belief that low serotonin causes depression, there’s another possible cause that could be explained by SSRIs’ effectiveness: Reduced neuroplasticity has been linked with depression.
Stress and other negative emotions can cause changes in your neuroplasticity. Neuroplasticity is the brain’s ability to form and reorganize synaptic connections. Think of it like the defragmentation of a computer’s hard drive. When you have good neuroplasticity, you can reorganize your storage quickly and easily. When you lack neuroplasticity, you struggle to learn new things and remember.
Changes to your neuroplasticity cause depression. Or depression may cause changes to your neuroplasticity. The studies aren’t yet clear on which happens first, but in either case, SSRIs can help improve your neuroplasticity.
If you’re feeling down or struggling with depression, there’s help. At Mental Health Hotline, we work with an extensive network of highly skilled mental health care providers to connect you with the help you need. Call us anytime — there’s always someone on the other end of the line.