Which brain chemicals are involved in antidepressants?

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There are several theories as to what causes depression, which is most likely the result of a complex interplay of individual factors, but one of the most widely accepted explanations for that brain chemistry is abnormal. In cases of unknown cause, the hypothesis that brain chemicals cause depression may be helpful.

1. Brain Chemistry and Depression

People with depression relate past events back to a specific element, such as a traumatic event in their life. However, it is not uncommon for people with depression to know the cause. They may even feel as though they have no "reason" to be depressed. In it, the hypothesis of an imbalance of chemicals in the brain plays an important role.
Researchers have suggested that for some people, having too little of certain substances in the brain (called neurotransmitters) can contribute to depression. Restoring the balance of brain chemicals can help alleviate symptoms — which is where different types of antidepressants can come in.
Even with the help of medications that help balance specific neurotransmitters in the brain, depression is still a very complex condition to treat. Even things that have worked well for someone in the past can become less effective over time, or even stop working, for these reasons that researchers are still trying to find. understand.
Researchers continue to try to understand the mechanisms of depression, including brain chemicals, in hopes of finding an explanation for these complexities and developing effective treatments than. Depression is a multifaceted condition, but awareness of brain chemistry can be helpful to medical and mental health professionals, researchers, and many people with depression.

2. What are neurotransmitters?

Simply put, neurotransmitters are chemical messengers in the brain. The brain's nerve cells use neurotransmitters to communicate with each other. The messages they send are thought to play a role in mood regulation.
The space between 2 neurons is called a synapse. When the cell wants to communicate, neurotransmitters can be packaged and released from the terminal (axon) of the presynaptic cell. When a neurotransmitter packet crosses space, it can be received by receptors for a specific chemical on postsynaptic (dendrite) cells. For example, serotonin receptors receive serotonin molecules.
If there are any redundant molecules in space, the presynaptic cell assembles them and reprocesses them for use in another communication. Each type of neurotransmitter can carry a different message and play a unique role in making an individual's brain chemistry. An imbalance in these chemicals can contribute to mental health conditions like depression.

3. The role of the main neurotransmitter

The three neurotransmitters involved in depression are:
Dopamine Norepinephrine Serotonin There are other neurotransmitters that can send messages in the brain, including glutamate, GABA and acetylcholine. Researchers are still learning about the role of these brain chemicals in depression and other diseases, such as Alzheimer's disease and fibromyalgia.
3.1. Dopamine
Another substance that can play a role in mood is dopamine. Dopamine creates a positive feeling associated with reward or reinforcement that motivates us to continue with a task or activity. Dopamine is thought to play an important role in many pathologies affecting the brain, including Parkinson's and schizophrenia.
There is also evidence that reduced dopamine levels may contribute to depression in some people. When other treatments fail, drugs that affect the dopamine system are often added and can be helpful for some people with depression.
3.2. Norepinephrine
Norepinephrine is both a neurotransmitter and a hormone. It plays a role in the "fight or flight response" along with adrenaline. It helps to send messages from one neuron to the next.
In the 1960s, Joseph J. Schildkraut suggested that norepinephrine was the brain chemical of interest in depression when he formulated the "catecholamine" hypothesis of mood disorders.
Schildkraut suggests depression occurs when there is too little norepinephrine in certain brain circuits. Also, mania occurs when there are too many neurotransmitters in the brain.
There is evidence to support the hypothesis, however, it is not opposed by researchers. First, changes in norepinephrine levels did not affect mood in each person. Furthermore, drugs that specifically target norepinephrine can reduce depression in some people, but not others. Therefore, researchers now understand that having too little norepinephrine is not the only chemical cause of depression.

3.3 Serotonin
Another neurotransmitter is serotonin aka the "feel-good" chemical. In addition to helping regulate your mood, serotonin has a number of different jobs throughout the body from the gut to blood clotting to sexual function.
With regard to its role in depression, serotonin has taken center stage over the past few decades thanks to the advent of antidepressants such as Prozac (fluoxetine) and serotonin reuptake inhibitors. other selective (SSRI). As their name suggests, these drugs specifically act on serotonin molecules.
Researchers have been looking at serotonin's role in mood disorders for nearly 30 years. "The Permissive Hypothesis" by Arthur J. Prange, Jr. and Alec Coppen suggest that low serotonin levels also allow norepinephrine to drop, but that serotonin can be manipulated to indirectly increase norepinephrine. Newer antidepressants called serotonin norepinephrine reuptake inhibitors (SNRIs) like Effexor (venlafaxine) target both serotonin and norepinephrine. Tricyclic antidepressants (TCAs) also affect norepinephrine and serotonin, but they have the added effect of affecting histamine and acetylcholine. These substances produce side effects, such as dry mouth, blurred vision, constipation, and urination.
On the other hand, SSRIs do not affect histamine and acetylcholine and do not have the same side effects, and are safer from a cardiovascular point of view. As a result, doctors, psychiatrists, and people with depression tend to prefer them over older antidepressants like TCA.

4. Causes of low neurotransmitter levels

If low levels of neurotransmitters can contribute to depression, then an important question is what causes low levels of serotonin, norepinephrine or dopamine in the first place? When something goes wrong anywhere in this process, low levels of the neurotransmitter can result.
Research has pointed to several potential causes of chemical imbalances in the brain, including:
Molecules that help make neurotransmitters (specific enzymes) are in short supply None enough receptor sites to receive the neurotransmitter The presynaptic cell is retrieving the neurotransmitter before it has a chance to reach the receptor Too few molecules that make the neurotransmitter (presynaptic) chemicals) Too few specific neurotransmitters (eg, serotonin) are being produced Several emerging theories involve factors that promote lower levels, such as cellular stress ( especially mitochondria). there is no way to measure them consistently and accurately.

5. Current and Future Depression Treatment

5.1 Treating Current Depression
Understanding the nature of depression can help people better understand the treatments available. While psychotherapy is helpful for some people with depression, if there is a chemical imbalance in the brain, it may not be enough to resolve their depressive symptoms.
If a person finds that therapy alone is not helping them manage their depression, they may want to try medication. For some people, antidepressants combined with psychotherapy have been shown to be particularly effective at addressing their symptoms.
For more complex treatment, medication does not always work for people with depression. One study that evaluated the effectiveness of currently available antidepressants found that they only worked for about 60% of people with depression.
Even if your depression is primarily related to an imbalance of brain chemicals, depression affects both your inner and outer life. Therefore, medication alone may not be enough to address all of the ways that depression can affect you.
There is also research showing that neurotransmitter levels can be affected by factors other than medications and that psychotherapy can help a person learn about them. For example, stress can contribute to low levels of certain neurotransmitters.
While taking an antidepressant can help relieve symptoms, it doesn't necessarily address the cause of low levels. In this situation, therapy that improves stress management and reduces stress may be helpful.
5.2 Future treatment for depression
Researchers are studying other molecular pathways in the brain (including the lutaminergic, cholinergic, and opioid systems) to see what role they might play in depression. Possibly due to a simple deficiency in a specific brain chemical that is a trigger, some depressive symptoms may be related to the relative levels of each type of neurotransmitter in different regions. of the brain.
Rather than being a simple equation of some unknown factor causing low levels of one or more neurotransmitters and these low levels producing symptoms of depression, the factual basis of depression is much more complex. While this complexity is often evident to people living with depression, medical professionals and researchers are still trying to understand the complex nature of diagnosing and treating the condition.
For example, in addition to the role of neurotransmitters, we know that many factors are involved in causing depression, ranging from genetic factors and childhood experiences to daily life and other factors. Our relationship. Even inflammation is being explored as a potential contributing factor.

5.3 Fighting the stigma of chemical imbalance
Acknowledging the limitations of our current knowledge about depression and its treatment is important. In recent years, some researchers have expressed concern that pharmaceutical companies marketing antidepressants may be misleading consumers by oversimplifying or misrepresenting research on antidepressants. Brain chemistry of depression.
Sociological research has found that the stigma attached to depression (and its use of medication) is not necessarily alleviated by the chemical imbalance theory.
Some studies have found that when it comes to saying that depression is caused by a chemical imbalance, people tend to feel less confident in their ability to control their condition. Likely to feel the need to stay away from someone who is depressed (often out of fear that they are dangerous).
However, not all studies are negative. Several studies included in the 2012 meta-analysis indicate that one of the most effective ways to address and challenge societal stigmas against mental illness is to educate and discuss the conditions. and treatment — including being upfront and honest about what is still unknown or unclear.
Accepting how little we really know about the chemistry of depression can help us maintain attitudes and expectations toward depression medications. For those trying to find the right treatment, understanding the complex chemistry can give them peace of mind when a particular drug isn't working for them or if they need to try more than one. antidepressant drugs.
Understanding the complexity of depression can also be helpful for people who have been given hurtful advice, such as being told to "get out of it." It is not easier for anyone to forget they are depressed than it is for someone with diabetes to drop their blood sugar simply without thinking about it.
The reality of the limitations of our knowledge can help us remember that currently, there is no one-size-fits-all treatment for depression. More often than not an interdisciplinary approach is not required. At the very least, every person facing depression needs and deserves a support team.

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References: health.harvard.edu, webmd.com, mayoclinicproceedings.org, verywellmind.com