One day, these discoveries should lead to better, more individualized treatment see "From the lab to your medicine cabinet" , but that is likely to be years away. And while researchers know more now than ever before about how the brain regulates mood, their understanding of the biology of depression is far from complete.
What follows is an overview of the current understanding of the major factors believed to play a role in the causes of depression. Popular lore has it that emotions reside in the heart. Science, though, tracks the seat of your emotions to the brain. Certain areas of the brain help regulate mood. Researchers believe that — more important than levels of specific brain chemicals — nerve cell connections, nerve cell growth, and the functioning of nerve circuits have a major impact on depression.
Still, their understanding of the neurological underpinnings of mood is incomplete. Increasingly sophisticated forms of brain imaging — such as positron emission tomography PET , single-photon emission computed tomography SPECT , and functional magnetic resonance imaging fMRI — permit a much closer look at the working brain than was possible in the past.
An fMRI scan, for example, can track changes that take place when a region of the brain responds during various tasks. Use of this technology has led to a better understanding of which brain regions regulate mood and how other functions, such as memory, may be affected by depression. Areas that play a significant role in depression are the amygdala, the thalamus, and the hippocampus see Figure 1. Research shows that the hippocampus is smaller in some depressed people. For example, in one fMRI study published in The Journal of Neuroscience , investigators studied 24 women who had a history of depression.
The more bouts of depression a woman had, the smaller the hippocampus. Stress, which plays a role in depression, may be a key factor here, since experts believe stress can suppress the production of new neurons nerve cells in the hippocampus. Researchers are exploring possible links between sluggish production of new neurons in the hippocampus and low moods.
An interesting fact about antidepressants supports this theory. These medications immediately boost the concentration of chemical messengers in the brain neurotransmitters. Yet people typically don't begin to feel better for several weeks or longer. Experts have long wondered why, if depression were primarily the result of low levels of neurotransmitters, people don't feel better as soon as levels of neurotransmitters increase.
The answer may be that mood only improves as nerves grow and form new connections, a process that takes weeks. In fact, animal studies have shown that antidepressants do spur the growth and enhanced branching of nerve cells in the hippocampus. So, the theory holds, the real value of these medications may be in generating new neurons a process called neurogenesis , strengthening nerve cell connections, and improving the exchange of information between nerve circuits.
If that's the case, depression medications could be developed that specifically promote neurogenesis, with the hope that patients would see quicker results than with current treatments. Amygdala: The amygdala is part of the limbic system, a group of structures deep in the brain that's associated with emotions such as anger, pleasure, sorrow, fear, and sexual arousal.
The amygdala is activated when a person recalls emotionally charged memories, such as a frightening situation. Activity in the amygdala is higher when a person is sad or clinically depressed. This increased activity continues even after recovery from depression. Thalamus: The thalamus receives most sensory information and relays it to the appropriate part of the cerebral cortex, which directs high-level functions such as speech, behavioral reactions, movement, thinking, and learning.
Some research suggests that bipolar disorder may result from problems in the thalamus, which helps link sensory input to pleasant and unpleasant feelings. Hippocampus: The hippocampus is part of the limbic system and has a central role in processing long-term memory and recollection. Interplay between the hippocampus and the amygdala might account for the adage "once bitten, twice shy.
The hippocampus is smaller in some depressed people, and research suggests that ongoing exposure to stress hormone impairs the growth of nerve cells in this part of the brain. The ultimate goal in treating the biology of depression is to improve the brain's ability to regulate mood.
We now know that neurotransmitters are not the only important part of the machinery. But let's not diminish their importance either. They are deeply involved in how nerve cells communicate with one another. And they are a component of brain function that we can often influence to good ends. Neurotransmitters are chemicals that relay messages from neuron to neuron. An antidepressant medication tends to increase the concentration of these substances in the spaces between neurons the synapses.
In many cases, this shift appears to give the system enough of a nudge so that the brain can do its job better. How the system works. If you trained a high-powered microscope on a slice of brain tissue, you might be able to see a loosely braided network of neurons that send and receive messages. While every cell in the body has the capacity to send and receive signals, neurons are specially designed for this function.
Each neuron has a cell body containing the structures that any cell needs to thrive. Stretching out from the cell body are short, branchlike fibers called dendrites and one longer, more prominent fiber called the axon.
A combination of electrical and chemical signals allows communication within and between neurons. When a neuron becomes activated, it passes an electrical signal from the cell body down the axon to its end known as the axon terminal , where chemical messengers called neurotransmitters are stored. The signal releases certain neurotransmitters into the space between that neuron and the dendrite of a neighboring neuron. That space is called a synapse. As the concentration of a neurotransmitter rises in the synapse, neurotransmitter molecules begin to bind with receptors embedded in the membranes of the two neurons see Figure 2.
The release of a neurotransmitter from one neuron can activate or inhibit a second neuron. If the signal is activating, or excitatory, the message continues to pass farther along that particular neural pathway. If it is inhibitory, the signal will be suppressed. The neurotransmitter also affects the neuron that released it.
Once the first neuron has released a certain amount of the chemical, a feedback mechanism controlled by that neuron's receptors instructs the neuron to stop pumping out the neurotransmitter and start bringing it back into the cell. This process is called reabsorption or reuptake. Enzymes break down the remaining neurotransmitter molecules into smaller particles. When the system falters. Brain cells usually produce levels of neurotransmitters that keep senses, learning, movements, and moods perking along.
But in some people who are severely depressed or manic, the complex systems that accomplish this go awry. For example, receptors may be oversensitive or insensitive to a specific neurotransmitter, causing their response to its release to be excessive or inadequate. Or a message might be weakened if the originating cell pumps out too little of a neurotransmitter or if an overly efficient reuptake mops up too much before the molecules have the chance to bind to the receptors on other neurons.
Any of these system faults could significantly affect mood. Kinds of neurotransmitters. Scientists have identified many different neurotransmitters. Here is a description of a few believed to play a role in depression:. Every part of your body, including your brain, is controlled by genes. Genes make proteins that are involved in biological processes.
Throughout life, different genes turn on and off, so that — in the best case — they make the right proteins at the right time.
But if the genes get it wrong, they can alter your biology in a way that results in your mood becoming unstable. In a person who is genetically vulnerable to depression, any stress a missed deadline at work or a medical illness, for example can then push this system off balance. Mood is affected by dozens of genes, and as our genetic endowments differ, so do our depressions.
The hope is that as researchers pinpoint the genes involved in mood disorders and better understand their functions, depression treatment can become more individualized and more successful. Patients would receive the best medication for their type of depression.
But if you feel sad, hopeless, or empty for longer than 2 weeks post-childbirth, you may have postpartum depression. Symptoms of postpartum depression can range from mild to severe and can include :. Postpartum depression is thought to be triggered by the dramatic hormonal changes that take place after pregnancy.
Bipolar depression occurs in certain types of bipolar disorder when a person experiences a depressive episode. Bipolar disorder is a mental disorder that causes distinct changes in mood, energy, concentration, and the ability to carry out your day-to-day tasks. People having a depressive episode may :.
Symptoms during a depressive episode last every day for most of the day and can last for several days or weeks. If bipolar disorder is treated, many will experience fewer and less severe symptoms of depression, if they experience depressive episodes. These 7 treatments may help ease symptoms of bipolar depression.
Depression and anxiety can occur in a person at the same time. In fact, research has shown that over 70 percent of people with depressive disorders also have symptoms of anxiety. You can work with them to identify coexisting symptoms of anxiety and depression and how they can be treated.
Obsessive-compulsive disorder OCD is a type of anxiety disorder. It causes unwanted and repeated thoughts, urges, and fears obsessions. These fears cause you to act out repeated behaviors or rituals compulsions that you hope will ease the stress caused by the obsessions.
People diagnosed with OCD frequently find themselves in a loop of obsessions and compulsions. If you have these behaviors, you may feel isolated because of them. This can lead to withdrawal from friends and social situations, which can increase your risk for depression. Having one anxiety disorder can increase your odds for having another.
Up to 80 percent of people with OCD also have major depression episodes. This dual diagnosis is a concern with children, too. Their compulsive behaviors, which may be first developing at a young age, can make them feel unusual. That can lead to withdrawing from friends and can increase the chance of a child developing depression. Some individuals who have been diagnosed with major depression may also have symptoms of another mental disorder called psychosis.
People with the condition may also experience feelings of sadness, hopelessness, and irritability. The combination of the two conditions is particularly dangerous. Treatments include medications and electroconvulsive therapy ECT. Pregnancy is often an exciting time for people. However, it can still be common for a pregnant woman to experience depression. Symptoms of depression during pregnancy include:.
Treatment for depression during pregnancy may focus entirely on talk therapy and other natural treatments. Your healthcare provider may encourage you to try an alternative option until after the birth of your baby. The risks for depression can continue after the baby arrives. Postpartum depression , which is also called major depressive disorder with peripartum onset, is a serious concern for new mothers.
Recognizing the symptoms may help you spot a problem and seek help before it becomes overwhelming. Research has established a link between alcohol use and depression. People who have depression are more likely to misuse alcohol.
Out of the Drinking alcohol frequently can make symptoms of depression worse, and people who have depression are more likely to misuse alcohol or become dependent on it. Read the full list of 15 ways you may be able to avoid depression. Depression can be temporary, or it can be a long-term challenge.
However, treatment often makes symptoms more manageable. Managing symptoms of depression involves finding the right combination of medications and therapies. They can help you create a different treatment plan that may work better in helping you manage your condition. Depression hurts. And while we often pair this mental illness with emotional pain like sadness, crying, and feelings of hopelessness, research shows…. My task was finding a way of making them….
The author shares how she went from anxiety to a deep depression to actively considering suicide. Read this article to understand what it really feels…. In , While depression can affect a person psychologically, it also has the….
Watching a friend live with depression can be painful, but there are ways to help. Learn what to do, avoid, and how to recognize the signs of suicidal…. People who experience anhedonia have a decreased ability to feel pleasure. Learn causes, risk factors, and treatments for anhedonia. A SAD lamp can help alleviate symptoms of seasonal affective disorder. Learn more about SAD lamps, how to use them, features to look for, and products…. Bipolar disorder is a mental health condition that causes extreme fluctuations in thinking, mood, and behavior, known as depression and mania or….
Experts say mushrooms contain a number of nutrients, including potassium and B vitamins, that can boost physical as well as mental health.
Health Conditions Discover Plan Connect. Mental Health. Medically reviewed by Vara Saripalli, Psy. Depression symptoms. Some things that can help you cope with feelings of depression include getting enough sleep, eating a healthy diet, finding social support, and engaging in regular physical activity.
While depression can make these things more challenging, tackling one or two tasks each day can help improve your well-being. Some ways that you can support a friend or loved one with depression include offering support and avoiding judgment. Offer to help with tasks that your friend might be struggling with.
Let them know you care, ask them what you can do to help, and encourage them to talk to their doctor. Learn more about depression so you can better understand ways you can help. While depression appears to have some genetic risk factors, there is no identifiable gene for depression. You may have a genetic predisposition to depression, but this does not necessarily mean that you will develop the condition. Antidepressants can be effective, but they often take some time to begin working. While such medications may be used alone, they are also often prescribed in conjunction with psychotherapy.
A mood disorder refers to a broad class of mental health conditions, including depression and bipolar disorder, that primarily impact emotional states. People may experience prolonged periods of a significantly depressed or sad mood, or they may have episodes of an abnormally elevated or irritable mood to an extent that it causes distress and interferes with daily living. A psychiatric evaluation is an assessment utilized by psychiatrists to diagnose mental health conditions.
An evaluation often involves talking to your doctor about your symptoms, getting a physical exam, and filling out a questionnaire. This allows your doctor to gain insight into the nature and severity of your condition. Persistent depressive disorder PDD , previously known as dysthymia, is a chronic state of depression. It involves symptoms such as low mood, loss of interest, sleep changes, and appetite changes that last for at least two years.
Symptoms may vary in intensity over time. Psychosis is a mental state that involves losing contact with reality. People who experience psychosis may believe, see, hear, or feel things that are not real. Psychotic depression is a condition in which people experience psychotic symptoms such delusions and hallucinations alongside symptoms of depression. Seasonal affective disorder SAD , formally known as major depressive disorder with a seasonal pattern, is a mood disorder that occurs the same time each year.
People may experience feelings of depression, social withdrawal, and fatigue usually during the fall and winter. Postpartum depression, formally known as major depressive disorder with a peripartum onset, is a serious but treatable form of depression that generally occurs after giving birth.
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