Which of the following biological factors are responsible for depression?

Hi, I'm Dr. Craig Sawchuk, a clinical psychologist at Mayo Clinic. And I'm here to talk with you about depression. Whether you're looking for answers for yourself, a friend, or loved one, understanding the basics of depression can help you take the next step.

What is depression?

Depression is a mood disorder that causes feelings of sadness that won't go away. Unfortunately, there's a lot of stigma around depression. Depression isn't a weakness or a character flaw. It's not about being in a bad mood, and people who experience depression can't just snap out of it. Depression is a common, serious, and treatable condition. If you're experiencing depression, you're not alone. It honestly affects people of all ages and races and biological sexes, income levels and educational backgrounds. Approximately one in six people will experience a major depressive episode at some point in their lifetime, while up to 16 million adults each year suffer from clinical depression. There are many types of symptoms that make up depression. Emotionally, you may feel sad or down or irritable or even apathetic. Physically, the body really slows down. You feel tired. Your sleep is often disrupted. It's really hard to get yourself motivated. Your thinking also changes. It can just be hard to concentrate. Your thoughts tend to be much more negative. You can be really hard on yourself, feel hopeless and helpless about things. And even in some cases, have thoughts of not wanting to live. Behaviorally, you just want to pull back and withdraw from others, activities, and day-to-day responsibilities. These symptoms all work together to keep you trapped in a cycle of depression. Symptoms of depression are different for everyone. Some symptoms may be a sign of another disorder or medical condition. That's why it's important to get an accurate diagnosis.

What causes depression?

While there's no single cause of depression, most experts believe there's a combination of biological, social, and psychological factors that contribute to depression risk. Biologically, we think about genetics or a family history of depression, health conditions such as diabetes, heart disease or thyroid disorders, and even hormonal changes that happen over the lifespan, such as pregnancy and menopause. Changes in brain chemistry, especially disruptions in neurotransmitters like serotonin, that play an important role in regulating many bodily functions, including mood, sleep, and appetite, are thought to play a particularly important role in depression. Socially stressful and traumatic life events, limited access to resources such as food, housing, and health care, and a lack of social support all contribute to depression risk. Psychologically, we think of how negative thoughts and problematic coping behaviors, such as avoidance and substance use, increase our vulnerability to depression.

The good news is that treatment helps. Effective treatments for depression exist and you do have options to see what works best for you. Lifestyle changes that improve sleep habits, exercise, and address underlying health conditions can be an important first step. Medications such as antidepressants can be helpful in alleviating depressive symptoms. Therapy, especially cognitive behavioral therapy, teaches skills to better manage negative thoughts and improve coping behaviors to help break you out of cycles of depression. Whatever the cause, remember that depression is not your fault and it can be treated.

To help diagnose depression, your health care provider may use a physical exam, lab tests, or a mental health evaluation. These results will help identify various treatment options that best fit your situation.

Help is available. You don't have to deal with depression by yourself. Take the next step and reach out. If you're hesitant to talk to a health care provider, talk to a friend or loved one about how to get help. Living with depression isn't easy and you're not alone in your struggles. Always remember that effective treatments and supports are available to help you start feeling better. Want to learn more about depression? Visit mayoclinic.org. Do take care.

Depression is a mood disorder that causes a persistent feeling of sadness and loss of interest. Also called major depressive disorder or clinical depression, it affects how you feel, think and behave and can lead to a variety of emotional and physical problems. You may have trouble doing normal day-to-day activities, and sometimes you may feel as if life isn't worth living.

More than just a bout of the blues, depression isn't a weakness and you can't simply "snap out" of it. Depression may require long-term treatment. But don't get discouraged. Most people with depression feel better with medication, psychotherapy or both.

Depression care at Mayo Clinic

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Symptoms

Although depression may occur only once during your life, people typically have multiple episodes. During these episodes, symptoms occur most of the day, nearly every day and may include:

  • Feelings of sadness, tearfulness, emptiness or hopelessness
  • Angry outbursts, irritability or frustration, even over small matters
  • Loss of interest or pleasure in most or all normal activities, such as sex, hobbies or sports
  • Sleep disturbances, including insomnia or sleeping too much
  • Tiredness and lack of energy, so even small tasks take extra effort
  • Reduced appetite and weight loss or increased cravings for food and weight gain
  • Anxiety, agitation or restlessness
  • Slowed thinking, speaking or body movements
  • Feelings of worthlessness or guilt, fixating on past failures or self-blame
  • Trouble thinking, concentrating, making decisions and remembering things
  • Frequent or recurrent thoughts of death, suicidal thoughts, suicide attempts or suicide
  • Unexplained physical problems, such as back pain or headaches

For many people with depression, symptoms usually are severe enough to cause noticeable problems in day-to-day activities, such as work, school, social activities or relationships with others. Some people may feel generally miserable or unhappy without really knowing why.

Depression symptoms in children and teens

Common signs and symptoms of depression in children and teenagers are similar to those of adults, but there can be some differences.

  • In younger children, symptoms of depression may include sadness, irritability, clinginess, worry, aches and pains, refusing to go to school, or being underweight.
  • In teens, symptoms may include sadness, irritability, feeling negative and worthless, anger, poor performance or poor attendance at school, feeling misunderstood and extremely sensitive, using recreational drugs or alcohol, eating or sleeping too much, self-harm, loss of interest in normal activities, and avoidance of social interaction.

Depression symptoms in older adults

Depression is not a normal part of growing older, and it should never be taken lightly. Unfortunately, depression often goes undiagnosed and untreated in older adults, and they may feel reluctant to seek help. Symptoms of depression may be different or less obvious in older adults, such as:

  • Memory difficulties or personality changes
  • Physical aches or pain
  • Fatigue, loss of appetite, sleep problems or loss of interest in sex — not caused by a medical condition or medication
  • Often wanting to stay at home, rather than going out to socialize or doing new things
  • Suicidal thinking or feelings, especially in older men

When to see a doctor

If you feel depressed, make an appointment to see your doctor or mental health professional as soon as you can. If you're reluctant to seek treatment, talk to a friend or loved one, any health care professional, a faith leader, or someone else you trust.

When to get emergency help

If you think you may hurt yourself or attempt suicide, call 911 in the U.S. or your local emergency number immediately.

Also consider these options if you're having suicidal thoughts:

  • Call your doctor or mental health professional.
  • Contact a suicide hotline.
    • In the U.S., call or text 988 to reach the 988 Suicide & Crisis Lifeline, available 24 hours a day, seven days a week. Or use the Lifeline Chat. Services are free and confidential.
    • U.S. veterans or service members who are in crisis can call 988 and then press “1” for the Veterans Crisis Line. Or text 838255. Or chat online.
    • The Suicide & Crisis Lifeline in the U.S. has a Spanish language phone line at 1-888-628-9454 (toll-free).
  • Reach out to a close friend or loved one.
  • Contact a minister, spiritual leader or someone else in your faith community.

If you have a loved one who is in danger of suicide or has made a suicide attempt, make sure someone stays with that person. Call 911 or your local emergency number immediately. Or, if you think you can do so safely, take the person to the nearest hospital emergency room.

More Information

  • Depression (major depressive disorder) care at Mayo Clinic
  • Male depression: Understanding the issues
  • Nervous breakdown: What does it mean?
  • Pain and depression: Is there a link?
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What are the biological effects of depression?

This review summarized longitudinal evidence indicating that depression increased the onset risk of a multitude of somatic disorders including, for example, cardiovascular, stroke, diabetes and obesity morbidity. These somatic consequences may partly be due to biological dysregulation present among depressed patients.

Which of the following are biological explanations of depression?

A biological explanation for depression is the monoamine hypothesis. Monoamines are a group of neurotransmitters that regulate mood; they include serotonin, noradrenaline and dopamine.