What Causes Depression?

Conditions list medically reviewed by George Krucik, MD, MBA

Depression is classified as a mood disorder. It may be described as feelings of sadness, loss, or anger that interfere with a person’s everyday activities. It is estimated that depression affects 1 in 20 Americans. People experience depression in... Read More

Depression is classified as a mood disorder. It may be described as feelings of sadness, loss, or anger that interfere with a person’s everyday activities. It is estimated that depression affects 1 in 20 Americans.

People experience depression in different ways. It may interfere with your daily work, resulting in lost time and lower productivity. It also can influence relationships and some chronic health conditions. Conditions that can get worse due to depression include:

  • arthritis
  • asthma
  • cardiovascular disease
  • cancer
  • diabetes
  • obesity

It’s important to realize that feeling down at times is a normal part of life. Sad and distressful events occur in everyone’s life. However, feeling miserable and hopeless on a consistent basis is not normal. Depression should be treated as a serious medical condition.

Left untreated, depression may last for months or years. It can worsen over time. Yet, those who seek treatment often see improvements in symptoms in just a few weeks.

Types of depression

Depression ranges in how serious it is. Some people experience mild and temporary episodes of sadness. Others experience severe and ongoing depressive episodes. Your doctor can help you come up with a treatment plan based on what type of depression you have. There are two main types: major depressive disorder and persistent depressive disorder.

Major depressive disorder

Major depressive disorder is the most severe form of depression. It is characterized by persistent feelings of sadness, hopelessness, and worthlessness that do not go away on their own. You must experience five or more of the following symptoms over a two-week period to be diagnosed with clinical depression:

  • feeling depressed most of the day
  • loss of interest in most regular activities
  • significant weight loss or gain
  • sleeping too much or not being able to sleep
  • slowed thinking or movement
  • fatigue or low energy most days
  • feelings of worthlessness or guilt
  • loss of concentration or indecisiveness
  • recurring thoughts of death or suicide

There are different subtypes of major depressive disorder, including:

Persistent depressive disorder

Persistent depressive disorder (PDD) used to be called dysthymia. It’s a mild, but chronic, form of depression. Symptoms often last for at least two years. PDD can affect your life more than clinical depression because it lasts for a longer period. It’s common for people with PDD to:

  • lose interest in normal daily activities
  • feel hopeless
  • lack productivity
  • have low self-esteem

People with PDD may be regarded as critical and unable to have fun.

Other forms of depression and mood disorders may have unique characteristics or develop under specific circumstances, making them difficult to classify. A few examples are described below.

Causes of depression

There are several possible causes of depression. Early childhood trauma can cause depression. This is because some events impact the way the body reacts to fear and stressful situations. Some people develop depression because of their genetics. You are more likely to develop it if you have a family history of depression or another mood disorder.

Other common causes include:

  • brain structure: there's a greater risk for depression if the frontal lobe of your brain is less active
  • medical conditions, such as a chronic illness, insomnia, chronic pain, or attention deficit hyperactivity disorder
  • a history of abusing drugs and alcohol

Many other people will have no discernable cause for their depression.

About 30 percent of people who have a substance abuse problem also experience depression. In addition to these causes, other risk factors for depression include:

  • low self-esteem or being self-critical
  • personal history of mental illness
  • certain medications
  • stressful events, such as loss of a loved one, economic problems, or a divorce

Diagnosing depression

There isn’t a single test to diagnose depression. However, your doctor can make a diagnosis based on your symptoms and a psychological evaluation. In most cases, your doctor will ask a series of questions about your moods, appetite, sleep pattern, activity level, and thoughts.

Because depression can be linked to other health problems, your doctor may also conduct a physical examination and order blood work. Sometimes thyroid problems or a vitamin D deficiency can trigger symptoms of depression.

Do not ignore symptoms of depression. If your mood doesn’t improve or gets worse, seek medical help. Depression is a serious mental illness with risks of complications. Depression not only affects you, but also your loved ones. If left untreated, complications include:

  • weight gain or loss
  • physical pain
  • substance abuse problems
  • panic attacks
  • relationship problems
  • social isolation
  • suicidal thoughts
  • self-mutilation

Treatment for depression

Living with depression can be difficult, but treatment can help you cope. Talk to your doctor about possible options. You may successfully manage symptoms with one form of treatment. It is also common to combine conventional and lifestyle therapies, including the following.

Medications: Your doctor may prescribe antidepressants, antianxiety, or antipsychotic medications.

Psychotherapy: Speaking with a therapist can help you learn skills to cope with negative feelings. You may also benefit from family or group therapy sessions.

Light therapy: Exposure to doses of white light can help regulate mood and improve symptoms of depression. This therapy is commonly used in seasonal affective disorder (which is now called major depressive disorder with seasonal pattern).

Alternative therapies: Ask your doctor about acupuncture or meditation. Some herbal supplements are also used to treat depression, such as St. John’s Wort, SAMe, and fish oil.

Talk with your doctor before taking a supplement or combining a supplement with prescription medication. Doing this will help prevent complications and side effects. Some supplements may worsen depression or reduce the effectiveness of medication.

Exercise: Aim for 30 minutes of physical activity three to five days a week. Exercise can increase your body's production of endorphins, which are hormones that improve your mood.

Avoid alcohol and drugs: Drinking or using drugs may make you feel better for a little bit. But in the long run, these substances can worsen depression and anxiety symptoms.

Learn how to say no: Feeling overwhelmed can worsen anxiety and depression symptoms. Setting boundaries in your professional and personal life can help you feel better.

Take care of yourself: You can also improve symptoms of depression by taking care of yourself. This includes getting plenty of sleep, eating a healthy diet, avoiding negative people, and participating in enjoyable activities.

Sometimes depression doesn't respond to medication. Your doctor may recommend other treatment options if your symptoms don’t improve. These include electroconvulsive therapy to stimulate the brain and treat major depression, or transcranial magnetic stimulation to stimulate nerve cells and regulate your moods.

Outlook for depression

Depression can be temporary, or a long-term challenge. Treatment doesn’t always make your depression go away completely. However, treatment often makes symptoms more manageable. Stick with your doctor’s recommended treatment plan, and regularly discuss your progress with your doctor. Controlling symptoms of depression involves finding the right combination of medications and therapies. If one treatment doesn’t work, you may have better results with a different one.

Medically reviewed by Timothy J. Legg, PhD, CRNP on December 8, 2016Written by Valencia Higuera


43 possible conditions

This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.

Conditions list medically reviewed by George Krucik, MD, MBA