Posts Tagged neurotransmitter
Gamma-aminobutyric acid (GABA) is a neurotransmitter, or chemical messenger, in the brain. It blocks specific signals in the central nervous system, slowing down the brain. This provides a protective and calming effect on the brain and body.
The body produces GABA, and it may also be present in some fermented foods, such as kimchi, miso, and tempeh. These are not foods that most people include in their daily diets, so some people take GABA supplements to achieve the benefits.
In this article, we examine how increased levels of GABA may impact the brain and body, and whether taking GABA supplements could have the same benefits.
What is GABA?
GABA is a neurotransmitter that inhibits or slows the brain’s functions. This activity produces effects such as:
The brain naturally releases GABA at the end of a day to promote sleepiness and allow a person to rest. Some of the medications doctors prescribe to induce sleep and reduce anxiety may also increase the action of GABA.
Medical benefits of increased GABA
Some experts have suggested that increased levels of GABA may have benefits, but the evidence is not clear. According to a 2019 review, GABA has anti-microbial, anti-seizure, and antioxidant properties and may help treat and prevent conditions such as:
Medications to increase GABA
Doctors may prescribe medicines that increase the amount of GABA or stimulate the same neurotransmitters in the brain to treat some medical conditions, such as epilepsy.
For example, benzodiazepines (Valium, Xanax) act on many of the same neurotransmitter receptors as GABA. According to one study, people who have depression may have reduced GABA levels in the brain. The use of benzodiazepines may be beneficial in those instances.
Doctors also prescribe the medication gabapentin (Neurontin), which is chemically similar to GABA to reduce seizures and muscle pain.
However, doctors are not clear whether the therapeutic effects of these medications are related to their effect on GABA receptors or whether they work in other ways.
GABA as a supplement
Some people take supplements of GABA for their supposed stress- and anxiety-relieving benefits.
The Food and Drug Administration (FDA) has approved GABA for use as a supplement and as a food additive. Manufacturers may add GABA to:
- sports drinks
- snack bars
- chewing gum
- candies, and more
Manufacturers produce GABA supplements by fermenting a form of lactic acid bacteria.
However, the FDA do not regulate dietary supplements in the same way as medications. Therefore, consumers should exercise caution as to where they purchase the product from and only buy from reputable vendors and companies.
How to use GABA supplements
Some people may take a supplement in pill form, while others may add it to foods, such as protein drinks.
Researchers have not established a daily recommended intake or a suggested upper limit for GABA. Anyone wanting to take GABA as a supplement should consider talking to their doctor first.
At present, there is not enough research to evaluate the possible side effects of taking GABA supplements. However, if a person does experience side effects that might be GABA-related, they should discontinue the use of the supplement and contact their doctor.
Benefits of taking GABA supplements
Some researchers have voiced concerns about the supposed positive benefits of taking GABA supplements. An article in the journal Frontiers in Psychology notes that experts remain unclear whether GABA offers real benefits or whether the effects that people report experiencing are a placebo response.
Other researchers do not believe that GABA supplements cross the blood-brain barrier, which they would have to do to have any effect on the body.
However, some studies report positive effects from taking GABA supplements. These include:
Enhanced thinking and task performance abilities
A study from 2015 found that taking 800 milligrams (mg) of GABA supplementation per day enhanced a person’s ability to prioritize and plan actions. Although the study was small, involving just 30 healthy volunteers, it showed how GABA supplementation might promote enhanced thinking.
An older study from 2012 found that taking 100 mg of GABA daily helped reduce stress due to mental tasks. Like many other studies related to GABA, the study was small and involved just 63 participants.
Workout recovery and muscle building
The participants performed the same resistance training exercises twice a week, and the researchers measured the results. The researchers found that the combination of whey protein and GABA increased levels of growth hormone compared to whey protein alone.
Although this was another small study, the researchers concluded that GABA supplements might help to build muscle and assist in workout recovery. They recommended that researchers conduct more studies.
GABA naturally plays an essential role in promoting sleep, relieving anxiety, and protecting the brain.
Scientists have not been able to prove the positive effects of GABA supplementation on a large scale, and their use may have limited effectiveness.
If a person has received a diagnosis for conditions such as depression, anxiety, or attention deficit hyperactivity disorder, they may wish to talk to their doctor about medically-proven treatment before taking GABA supplements.
Everything you need to know about chemical imbalances in the brain
A chemical imbalance in the brain occurs when a person has either too little or too much of certain neurotransmitters.
Neurotransmitters are the chemical messengers that pass information between nerve cells. Examples of neurotransmitters include serotonin, dopamine, and norepinephrine.
People sometimes call serotonin and dopamine the “happy hormones” because of the roles that they play in regulating mood and emotions.
While this theory may hold some truth, it runs the risk of oversimplifying mental illnesses. In reality, mood disorders and mental health illnesses are highly complex conditions that affect 46.6 million adults living in the United States alone.
In this article, we discuss conditions with links to chemical imbalances in the brain, myths surrounding this theory, possible treatment options, and when to see a doctor.
Although chemical imbalances in the brain seem to have an association with mood disorders and mental health conditions, researchers have not proven that chemical imbalances are the initial cause of these conditions.
Other factors that contribute to mental health conditions include:
- genetics and family history
- life experiences, such as a history of physical, psychological, or emotional abuse
- having a history of alcohol or illicit drug use
- taking certain medications
- psychosocial factors, such as external circumstances that lead to feelings of isolation and loneliness
While some studies have identified links between distinct chemical imbalances and specific mental health conditions, researchers do not know how people develop chemical imbalances in the first place.
Current biological testing also cannot reliably verify a mental health condition. Doctors do not, therefore, diagnose mental health conditions by testing for chemical imbalances in the brain. Instead, they make a diagnosis based on a person’s symptoms and the findings of a physical examination.
What conditions are linked to chemical imbalances?
Research has linked chemical imbalances to some mental health conditions, including:
Depression, also called clinical depression, is a mood disorder that affects many aspects of a person’s life, from their thoughts and feelings to their sleeping and eating habits.
Although some research links chemical imbalances in the brain to depression symptoms, scientists argue that this is not the whole picture.
For example, researchers point out that if depression were solely due to chemical imbalances, treatments that target neurotransmitters, such as selective serotonin reuptake inhibitors (SSRIs), should work faster.
The symptoms of depression vary widely among individuals, but they can include:
- persistent feelings of sadness, hopelessness, anxiety, or apathy
- persistent feelings of guilt, worthlessness, or pessimism
- loss of interest in formerly enjoyable activities or hobbies
- difficulty concentrating, making decisions, or remembering things
- restlessness or hyperactivity
- insomnia or sleeping too much
- changes in appetite and weight
- physical aches, cramps, or digestive problems
- thoughts of suicide
Many different types of depression exist. These include:
- major depressive disorder (MDD)
- persistent depressive disorder
- psychotic depression
- postpartum depression
- seasonal affective disorder (SAD)
The dramatic hormonal changes that take place after giving birth are among the factors that can increase a woman’s risk of developing postpartum depression. According to the National Institute of Mental Health, 10–15% of women experience postpartum depression.
Bipolar disorder is a mood disorder that causes alternating periods of mania and depression. These periods can last anywhere from a few days to a few years.
Mania refers to a state of having abnormally high energy. A person experiencing a manic episode may exhibit the following characteristics:
- feeling elated or euphoric
- having unusually high levels of energy
- participating in several activities at once
- leaving tasks unfinished
- talking extremely fast
- being agitated or irritable
- frequently coming into conflict with others
- engaging in risky behavior, such as gambling or drinking excessive quantities of alcohol
- a tendency to experience physical injuries
Severe episodes of mania or depression can cause psychotic symptoms, such as delusions and hallucinations.
People who have bipolar disorder can experience distinct changes in their mood and energy levels. They may have an increased risk of substance abuse and a higher incidence of certain medical conditions, such as:
The exact cause of bipolar disorder remains unknown. Researchers believe that changes in the dopamine receptors — resulting in altered dopamine levels in the brain — may contribute to the symptoms of bipolar disorder.
However, people who have an anxiety disorder often experience persistent anxiety or excessive worry that worsens in response to stressful situations.
The GABA neurotransmitter reduces neuronal activity in the amygdala, which is the part of the brain that stores and processes emotional information.
GABA is not the only neurotransmitter that anxiety disorders involve. Other neurotransmitters that may contribute to these disorders include:
- corticotropin-releasing hormone
- opioid peptides
- neuropeptide Y
Doctors can prescribe a class of medications called psychotropics to rebalance the concentration of particular neurochemicals in the brain.
Doctors use these medications to treat a range of mental health conditions, including depression, anxiety, and bipolar disorder.
Examples of psychotropics include:
- Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (Prozac), citalopram (Celexa), and sertraline (Zoloft).
- Serotonin-norepinephrine reuptake inhibitors (SNRIs), including venlafaxine (Effexor XR), duloxetine (Cymbalta), and desvenlafaxine (Pristiq).
- Tricyclic antidepressants (TCAs), such as amitriptyline (Elavil), desipramine (Norpramin), and nortriptyline (Pamelor).
- Benzodiazepines, including clonazepam (Klonopin) and lorazepam (Ativan).
While some people experience reduced symptoms within a few weeks, it can sometimes take months for others to feel the effects.
Different psychotropics have varying side effects. People can discuss the benefits and risks of these medications with their doctor.
The side effects of psychotropic medications can include:
- If you know someone at immediate risk of self-harm, suicide, or hurting another person:
- Call 911 or the local emergency number.
- Stay with the person until professional help arrives.
- Remove any weapons, medications, or other potentially harmful objects.
- Listen to the person without judgment.
- If you or someone you know is having thoughts of suicide, a prevention hotline can help. The National Suicide Prevention Lifeline is available 24 hours a day at 1-800-273-8255.
When to see a doctor
These symptoms should not cause alarm if they are mild and resolve within a few days.
However, people may wish to consider speaking with a doctor or trained mental health professional if they experience emotional, cognitive, or physical symptoms every day for more than 2 weeks.
Mental health is complex and multifaceted, and numerous factors can affect a person’s mental well-being.
Although chemical imbalances in the brain may not directly cause mental health disorders, medications that influence the concentration of neurotransmitters can sometimes provide symptom relief.
People who experience signs and symptoms of a mental health problem for more than 2 weeks may wish to speak to a doctor.
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.
Dopamine is a chemical found naturally in the human body. It is a neurotransmitter, meaning it sends signals from the body to the brain.
Dopamine plays a part in controlling the movements a person makes, as well as their emotional responses. The right balance of dopamine is vital for both physical and mental wellbeing.
Vital brain functions that affect mood, sleep, memory, learning, concentration, and motor control are influenced by the levels of dopamine in a person’s body. A dopamine deficiency may be related to certain medical conditions, including depression and Parkinson’s disease.
A dopamine deficiency can be due to a drop in the amount of dopamine made by the body or a problem with the receptors in the brain.
The symptoms of a dopamine deficiency depend on the underlying cause. For example, a person with Parkinson’s disease will experience very different symptoms from someone with low dopamine levels due to drug use.
Some signs and symptoms of conditions related to a dopamine deficiency include:
- muscle cramps, spasms, or tremors
- aches and pains
- stiffness in the muscles
- loss of balance
- difficulty eating and swallowing
- weight loss or weight gain
- gastroesophageal reflux disease (GERD)
- frequent pneumonia
- trouble sleeping or disturbed sleep
- low energy
- an inability to focus
- moving or speaking more slowly than usual
- feeling fatigued
- feeling demotivated
- feeling inexplicably sad or tearful
- mood swings
- feeling hopeless
- having low self-esteem
- feeling guilt-ridden
- feeling anxious
- suicidal thoughts or thoughts of self-harm
- low sex drive
- lack of insight or self-awareness
Low dopamine is linked to numerous mental health disorders but does not directly cause these conditions.
The most common conditions linked to a dopamine deficiency include:
In Parkinson’s disease, there is a loss of the nerve cells in a specific part of the brain and loss of dopamine in the same area.
It is also thought that drug abuse can affect dopamine levels. Studies have shown that repeated drug use could alter the thresholds required for dopamine cell activation and signaling.
Damage caused by drug abuse means these thresholds are higher and therefore it is more difficult for a person to experience the positive effects of dopamine. Drug abusers have also been shown to have significant decreases in dopamine D2 receptors and dopamine release.
Diets high in sugar and saturated fats can suppress dopamine, and a lack of protein in a person’s diet could mean they do not have enough l-tyrosine, which is an amino acid that helps to build dopamine in the body.
Some studies have found that people who are obese are more likely to be dopamine deficient too.
There is no reliable way to measure levels of dopamine in a person. However, a doctor may look at a person’s symptoms, lifestyle factors, and medical history to determine if they have a condition related to low levels of dopamine.
If a person is diagnosed with a mental health condition, such as depression or schizophrenia, a doctor may prescribe medications to help with the symptoms. These drugs may include anti-depressants and mood stabilizers.
Ropinirole and pramipexole can boost dopamine levels and are often prescribed to treat Parkinson’s disease. Levodopa is usually prescribed when Parkinson’s is first diagnosed.
Other treatments for a dopamine deficiency may include:
- changes in diet and lifestyle
- physical therapy for muscle stiffness and movement problems
Activities that make a person feel happy and relaxed are also thought to increase dopamine levels. These may include exercise, therapeutic massage, and meditation.
Dopamine vs. serotonin
Dopamine and serotonin are both naturally occurring chemicals in the body that have roles in a person’s mood and wellbeing.
Serotonin influences a person’s mood and emotions, as well as sleep patterns, appetite, body temperature, and hormonal activity, such as the menstrual cycle.
Some researchers believe that low levels of serotonin contribute to depression. The relationship between serotonin and depression and other mood disorders is complex and unlikely to be caused by a serotonin imbalance alone.
Additionally, dopamine affects how a person’s moves, but there is no clear link to the role of serotonin in movement.
Dopamine deficiency can have a significant impact on a person’s quality of life, affecting them both physically and mentally. Many mental health disorders are linked to low levels of dopamine. Other medical conditions, including Parkinson’s disease, have also been linked to low dopamine.
There is limited evidence that diet and lifestyle can affect the levels of dopamine a person creates and transmits in their body. Certain medications and some therapies may help relieve symptoms, but a person should always speak to a doctor first if they are concerned about their dopamine levels.
Depression is characterized by persistent low mood and feelings of hopelessness, and it is one of the most common mental disorders in the United States. In 2014, there were an estimated 15.7 million U.S. adults who experienced at least one major depressive episode, representing around 6.7 percent of the country’s adults.
Treatments for depression generally include talking therapies in conjunction with medication. The class of drugs most commonly prescribed is selective serotonin reuptake inhibitors (SSRIs), and these include brands such as Prozac and Zoloft.
SSRIs can help some people with depression, but they are not perfect; not everyone responds well to them, and side effects including nausea, insomnia, agitation, and erectile dysfunction can be unpleasant.
Also, SSRIs can take some time to kick in; although some people might feel some benefit within hours or even minutes, most people do not feel the full antidepressant effect until they have been taking the drugs for weeks or even months.
How do SSRIs work?
In the brain, messages are sent between neurons by releasing neurotransmitters into a gap between the cells, or the synapse. Serotonin is one such neurotransmitter. It is released from the first neuron and binds to receptors on the second neuron.
Normally, once serotonin has been released into the synapse and relayed its message, the majority is reabsorbed into the first nerve cell for reuse at a later date. SSRIs prevent serotonin from being reabsorbed. In this way, they ensure that serotonin hangs around in the synapse for a longer time, exerting more of an effect.
Although SSRIs have been known to medical science since the 1950s, their exact mechanism is not understood. This is because there are at least 1,000 types of neuron that can be influenced by a surge in serotonin, and some of these neurons may be excited, while others might be inhibited.
The mixed response is because there are 14 subtypes of serotonin receptor throughout the body and any single nerve could have a cocktail of receptor types. Teasing out which receptor subtype is playing the most significant role has proven challenging.
The role of the dentate gyrus
A group of scientists from Rockefeller University in New York City, NY, recently set out to take a closer look at the action of SSRIs on a particular type of nerve cell. The team was headed up by Lucian Medrihan and Yotam Sagi, both research associates in the Laboratory of Molecular and Cellular Neuroscience, and Paul Greengard, Nobel laureate.
Their findings were recently published in the journal Neuron.
“Many different types of synapses throughout the brain use serotonin as their neurotransmitter. An issue of major importance has been to identify where in the myriad of neurons the antidepressants initiate their pharmacological action.”
The team concentrated on a group of cells in the dentate gyrus (DG). According to the authors, they chose the DG because previous work has established that “SSRI treatment promotes a variety of synaptic, cellular, and network adaptations in the DG.”
Specifically, the team investigated cholecystokinin (CCK)-expressing neurons within the DG. These neurons were of interest because they are heavily influenced by neurotransmitter systems that are associated with mood disorders, such as depression.
Finding the right receptor
Using a technique called translating ribosome affinity purification, the team were able to identify the serotonin receptors on CCK cells. Sage explains, “We were able to show that one type of receptor, called 5-HT2A, is important for SSRIs’ long-term effect, while the other, 5-HT1B, mediates the initiation of their effect.
The next step in the study involved efforts to mimic SSRIs’ effects by manipulating CCK neurons in mice. They used chemogenetics to switch nerve cells on or off and implanted tiny electrodes inside the mouse brains.
The findings were clear. When the CCK neurons were inhibited, the pathways important for the mediation of SSRI responses lit up. In other words, the scientists had recreated a Prozac-like effect without using the drug.
To back up these findings, the team used behavioral experiments in a pool and observed swimming patterns. Again, silencing the CCK neurons created behavior that was similar to that displayed by the mice that had been given SSRIs: they swam for longer with increased vigor.
According to the researchers, understanding the importance of the DG and the specific cells important for treating depression will help to design faster-acting, more effective antidepressants with fewer side effects.
The work was carried out using techniques that would have been impossible just 5 years ago, and the studies that follow are likely to improve our understanding even further.
PHILADELPHIA – Epilepsy affects more than 65 million people worldwide. One-third of these patients have seizures that are not controlled by medications. In addition, one-third have brain lesions, the hallmark of the disease, which cannot be located by conventional imaging methods.
Researchers at the Perelman School of Medicine at the University of Pennsylvania have piloted a new method using advanced noninvasive neuroimaging to recognize the neurotransmitter glutamate, thought to be the culprit in the most common form of medication-resistant epilepsy. Their work is published today in Science Translational Medicine.
Glutamate is an amino acid which transmits signals from neuron to neuron, telling them when to fire. Glutamate normally docks with the neuron, gives it the signal to fire and is swiftly cleared. In patients with epilepsy, stroke and possibly ALS, the glutamate is not cleared, leaving the neuron overwhelmed with messages and in a toxic state of prolonged excitation.
In localization-related epilepsy, the most common form of medication-resistant epilepsy, seizures are generated in a focused section of the brain; in 65 percent of patients, this occurs in the temporal lobe. Removal of the seizure-generating region of the temporal lobe, guided by preoperative MRI, can offer a cure. However, a third of these patients have no identified abnormality on conventional imaging studies and, therefore, more limited surgical options.
Current antidepressants take around 3 to 8 weeks to kick in and only help around 50% of people who are depressed.
A new type of antidepressant holds the promise of treating depression quickly, without too many side-effects. Professor Scott Thompson, of the University of Maryland School of Medicine who led the research, said:
“Our results open up a whole new class of potential antidepressant medications.
We have evidence that these compounds can relieve the devastating symptoms of depression in less than one day, and can do so in a way that limits some of the key disadvantages of current approaches.”
Currently used antidepressants, such as Prozac and Lexapro, target levels of the neurotransmitter serotonin.
Unfortunately they are only effective in around half of people with depression. Even amongst people they do help, it can take three to eight weeks for the effects can be felt. For patients who are suicidal, this period can be excruciating.
Also, many now believe that targeting serotonin is not effective (see: Long-Held Belief About Depression Challenged by New Study).
The new compounds focus on another neurotransmitter with the acronym GABA (gamma-aminobutyric acid), instead of serotonin. GABA mainly reduces brain activity in certain key areas related to mood.
The new class of compounds dampen down these inhibitory signals. Theoretically, the result should be to lift mood.
Professor Thompson explained that preliminary tests on animals have been encouraging:
“These compounds produced the most dramatic effects in animal studies that we could have hoped for.
It will now be tremendously exciting to find out whether they produce similar effects in depressed patients.
If these compounds can quickly provide relief of the symptoms of human depression, such as suicidal thinking, it could revolutionize the way patients are treated.”
The study found that the compounds only affected the brains of stressed rats and left unstressed rats unchanged. This may mean that the side-effects of the treatment will be less severe than those seen for current antidepressants.
The study was published in the journal Neuropsychopharmacology (Fischell et al., 2015).