- Introduction to causes of depression
- What are the main causes of depression?
- How is biology related to depression?
- How is genetics linked to the risk of depression?
- Can certain drugs cause depression?
- What's the link between depression and chronic illness?
- Is depression linked to chronic pain?
- Does depression often occur with grief?
Introduction to causes of depression
Have you ever wondered what causes clinical depression? Perhaps you have been diagnosed with major depression, and that's made you question why some people get depressed while others don't.
Depression is an extremely complex disease. It occurs for a variety of reasons. Some people experience depression during a serious medical illness. Others may have depression with life changes such as a move or the death of a loved one. Still others have a family history of depression. Those who do may experience depression and feel overwhelmed with sadness and loneliness for no known reason.
What Are the Main Causes of Depression?
There are a number of factors that may increase the chance of depression, including the following:
- Abuse. Past physical, sexual, or emotional abuse can cause depression later in life.
- Certain medications. For example, some drugs used to treat high blood pressure, such as beta-blockers or reserpine, can increase your risk of depression.
- Conflict. Depression may result from personal conflicts or disputes with family members or friends.
- Death or a loss. Sadness or grief from the death or loss of a loved one, though natural, can also increase the risk of depression.
- Genetics. A family history of depression may increase the risk. It's thought that depression is passed genetically from one generation to the next. The exact way this happens, though, is not known.
- Major events. Even good events such as starting a new job, graduating, or getting married can lead to depression. So can moving, losing a job or income, getting divorced, or retiring.
- Other personal problems. Problems such as social isolation due to other mental illnesses or being cast out of a family or social group can lead to depression.
- Serious illnesses. Sometimes depression co-exists with a major illness or is a reaction to the illness.
- Substance abuse. Nearly 30% of people with substance abuse problems also have major or clinical depression.
How Is Biology Related to Depression?
Researchers have noted differences in the brains of people who are depressed as compared to people who are not. For instance, the hippocampus, a small part of the brain that is vital to the storage of memories, appears to be smaller in people with a history of depression than in those who've never been depressed. A smaller hippocampus has fewer serotonin receptors. Serotonin is a calming brain chemical known as a neurotransmitter that allows communication between nerves in the brain and the body. It's also thought that the neurotransmitter norepinephrine may be involved in depression.
Scientists do not know why the hippocampus is smaller in those with depression. Some researchers have found that the stress hormone cortisol is produced in excess in depressed people. These investigators believe that cortisol has a toxic or poisonous effect on the hippocampus. Some experts theorize that depressed people are simply born with a smaller hippocampus and are therefore inclined to suffer from depression.
One thing is certain -- depression is a complex illness with many contributing factors. The latest scans and studies of brain chemistry that show the effects of antidepressants help broaden our understanding of the biochemical processes involved in depression. As scientists gain a better understanding of the cause(s) of depression, health professionals will be able to make better "tailored" diagnoses and, in turn, prescribe more effective treatment plans.
How Is Genetics Linked to the Risk of Depression?
We know that depression seems to run in families. This suggests that there's a genetic link to depression. Children, siblings, and parents of people with severe depression are much more likely to suffer from depression than are members of the general population. Multiple genes interacting with one another in special ways probably contribute to the various types of depression that run in families. Yet despite all the evidence of a family link to depression, scientists still have not been able to identify a "depression" gene.
Can Certain Drugs Cause Depression?
In certain people, drugs may lead to depression. For example, medications such as barbiturates, benzodiazepines, and beta-blockers have been associated with depression, especially in older people. Likewise, medications such as corticosteroids, opioids (codeine, morphine), and anticholinergics taken to relieve stomach cramping have been found to cause mania, which is a highly elated state associated with bipolar disorder.
What's the Link Between Depression and Chronic Illness?
In some people, a chronic illness causes depression. A chronic illness is an illness that lasts for a very long time and usually cannot be cured completely. However, chronic illnesses can often be controlled through diet, exercise, lifestyle habits, and certain medications. Some examples of chronic illnesses that may cause depression are diabetes, heart disease, arthritis, kidney disease, HIV/AIDS, lupus, and multiple sclerosis (MS). Hypothyroidism may also lead to depressed feelings.
Researchers believe that treating the depression may also help the co-existing illness improve.
Is Depression Linked to Chronic Pain?
When pain lingers for weeks to months, it's referred to as being "chronic." Not only does chronic pain hurt, it also disturbs your sleep, your ability to exercise and be active, your relationships, and your productivity at work. Can you see how chronic pain may also leave you feeling sad, isolated, and depressed?
There is help for chronic pain and depression. A multifaceted program of medicine, psychotherapy, support groups, and more can help you manage your pain, ease your depression, and get your life back on track.
Does Depression Often Occur With Grief?
Grief is a common response to loss. Losses that may lead to grief include the death or separation of a loved one, loss of a job, death or loss of a beloved pet, or any number of other changes in life, such as divorce, becoming an "empty nester," or retirement. Anyone can experience grief and loss, but not everyone will experience depression. Each person is unique in how he or she copes with these feelings.
WebMD Medical Reference
Health Solutions From Our Sponsors
National Institute of Mental Health: "Causes of Depression."
SAMSHA's National Mental Health Information Center: "Mood Disorders."
National Institute of Mental Health: "What is Depression?"
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders: DSM-IV-TR, American Psychiatric Pub, 2000.
Fieve, R. Bipolar II, Rodale Books, 2006.
Reviewed by Brunilda Nazario, MD on February 01, 2012
© 2010 WebMD, LLC. All rights reserved.
Top Depression Related Articles
Childhood ADD or ADHD (Attention Deficit Hyperactivity Disorder in Children)Attention deficit hyperactivity disorder (ADHD) causes the following symptoms in children: excessive activity, problems concentrating, and difficulty controlling impulses. There are three types of ADHD: the predominantly inattentive type, the predominantly hyperactive/impulsive type, and the combined (inattentive, hyperactive, and impulsive) type. Stimulant medications are the most common medication used to treat ADHD.
Anorexia is an eating disorder characterized by markedly reduced appetite or total aversion to food. Anorexia is a serious psychological disorder and is a condition that goes well beyond out-of-control dieting. With anorexia, the drive to become thinner is actually secondary to concerns about control and/or fears relating to one's body. There are psychological and behavioral symptoms as well as physical symptoms of anorexia including: depression, social withdrawal, fatigue, food obsession, heart and gastrointestinal complications, kidney function, flaky skin, brittle nails, and tooth loss (this list is not exhaustive).
Bipolar Disorder QuizWho is at risk for developing bipolar disorder? Are you? Take this Bipolar Disorder Quiz to learn more about bipolar disorder, if you're at risk, and what you can do about it.
Bipolar SlideshowBipolar disorder (once called manic depression) causes extreme mood shifts and can be disorienting. Our experts define bipolar disorder, discuss bipolar symptoms, and describe bipolar medications that can help.
Chronic Fatigue Syndrome (CFS or SEID)Chronic fatigue syndrome (CFS) or systemic exertion intolerance disease (SEID) is a debilitating and complex disorder characterized by profound fatigue that lasts six months or longer, is not improved by bed rest, and may be worsened by physical or mental activity.
Cupping is a type of traditional Chinese medicine that stimulates the flow of chi (qi, or energy) within the body. There are a few different types of cupping: air, fire, wet, and the sliding cups technique. Cupping purports to bring impurities to the skin's surface and remove toxins. Oftentimes, cupping leaves marks, or bruises, on the skin.
Depression SlideshowWhat is depression? Get information on symptoms, signs, tests, and treatments for many types of depression including major depression, chronic depression, teen depression, and postpartum depression.
Depression QuizMany people do not recognize the symptoms and warning signs of depression and depressive disorders in children and adults. With proper diagnosis, treatments and medications are available. Take this quiz to learn more about recovery from depression.
Depression Tips SlidesThe right exercise, diet, and activities -- even playing with a pet --can help you recover from depression. Learn simple lifestyle changes you can do to improve your mood.
Electroconvulsive Therapy (ECT)Electroconvulsive therapy (ECT) involves passing an electrical current through the brain to produce controlled seizures. ECT is useful for patients with severe depression and for those who are suicidal. ECT is administered in a hospital setting under anesthesia. A common side effect is short-term memory loss.
FibromyalgiaFibromyalgia is a chronic pain condition characterized by symptoms such as fatigue, sleep disturbances, and tender points. Stress reduction, exercise, and medication are the standard treatments for fibromyalgia.
Human Immunodeficiency Virus (HIV)HIV (human immunodeficiency virus) infection left untreated causes AIDS (acquired immunodeficiency syndrome). Still incurable, AIDS describes immune system collapse that opens the way for opportunistic infections and cancers to kill the patient. Early symptoms and signs of HIV infection include flu-like symptoms and fungal infections, but some people may not show any symptoms for years. Highly active antiretroviral therapy (ART) is the standard treatment for HIV infection. These combination drug regimens have made HIV much less deadly, but a cure or vaccine for the pandemic remains out of reach. HIV is usually transmitted through sexual contact or sharing IV drug needles, but can also infect someone through contact with infected blood. Sexual abstinence, safe sex practices, quitting IV drugs (or at least using clean needles), and proper safety equipment by clinicians and first responders can drastically reduce transmission rates for HIV/AIDS.
Myths and Facts About Depression SlideshowFolk remedies and half-truths still prevent many from getting treatment for depression. WebMD's pictures show unusual symptoms in men, seniors, and others, along with many ways to recover.
Penis PumpVacuum constriction devices, or penis pumps, may be useful in the treatment of erectile dysfunction (impotence). A penis pump is an acrylic cylinder with a pump that can be attached to the end of the penis. The pump then creates a vacuum to help the penis become erect, while a constriction ring maintains the erection.
PsychotherapyPsychoteraphy is often the first form of treatment recommended for depression. Psychotherapy helps depression by helping people understand the behaviors, emotions and ideas that contribute to their depression, regain a sense of control and pleasure in life, and learn coping techniques as well as problem solving skills.
Vagus Nerve Stimulation (VNS) for Seizures
Vagus nerve stimulation (VNS) is a technique used to treat epilepsy. It involves implanting a pacemaker-like device that generates pulses of electricity to stimulate the vagus nerve. The vagus nerve is one of the 12 cranial nerves, the paired nerves that attach to the undersurface of the brain and relay information to and from the brain.