Depression, also referred to as clinical depression or major depressive disorder, is a medical condition that is classified as a mood disorder. It can affect how you feel and your ability to function on a day-to-day basis.

While everyone tends to feel sad or low from time to time, feeling that way for weeks or months at a time could mean you have depression.

If you suspect you may have depression, you’re not alone. Over 8% of adults living in the United States have experienced at least one major depressive episode.

Major depressive disorder is marked by symptoms such as sadness, loss of interest in previously enjoyed activities, difficulty concentrating, and changes in sleep and appetite. Causes include brain chemistry, genetics, and environmental factors. There are treatments available that can help, including therapy, medication, and lifestyle changes.

Everyone experiences depression differently. While some people may have a few symptoms, others may have many. The frequency, severity, and duration of the symptoms can also vary from person to person.

These are some of the symptoms of major depressive disorder you may experience:

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

For more mental health resources, see our National Helpline Database.

Depression may take different forms, or develop under certain circumstances. Accordingly, it may be classified into different types of depression, one of which is major depressive disorder.

The types of depression include:

The exact causes of major depressive disorder are not fully understood, but experts believe that several different factors cause it. Some factors that may contribute to the onset of major depressive disorder include genetics, stress, certain medical conditions, and brain chemistry.

Certain genetic, biological, psychological, and environmental factors can increase the chances of someone developing depression; however, it’s important to remember that anyone can develop depression.

The potential causes and risk factors for depression include:

Having differences in the levels of certain brain chemicals can make you more prone to developing depression. The most recent evidence indicates that chemical imbalances in the brain are not the primary cause of depression. Neurotransmitters like serotonin and dopamine do play an important role in mood, which is why antidepressant medications that affect neurotransmitter levels may be helpful.

Genes can play a role in depression. Having a relative with depression can increase your chances of developing depression.

Having a genetic risk for depression does not necessarily mean that you will develop the condition. Instead, it is believed that the interaction of genetic and environmental factors is what determines if someone experiences depression.

If you have a close relative with depression (such as a parent, sibling, or child), your risk of also developing the condition is around three times higher than that of the general population.

You may be more likely to develop depression if you have had it before. One of the best predictors of whether you will experience depression in the future is whether you've experienced it in the past.

Research suggests that around 70% of people who've had two episodes of major depressive disorder in the past will have a recurring episode in the future.

Women may be twice as likely to develop depression than men. Factors contributing to this increased risk include hormonal differences, socialization differences, and greater life stress.

Trauma, the death of a loved one, major life changes, and other upsetting events can cause depression. People who experience trauma in childhood have a higher risk of developing depression as adults.

Stress can affect you physically and mentally, and increase your risk of developing depression.

Lack of support and social isolation can increase the chances of developing depression. Unfortunately, social withdrawal is a common symptom of depression.

Depression may occur along with chronic or serious medical conditions like cancer, heart disease, diabetes, and Parkinson’s disease. Having depression can worsen these conditions.

Some medicines can cause depression as a side effect. Some medications that can have depression as a side effect include:

Substances such as alcohol or drugs can cause or exacerbate depression. Unfortunately, it is not uncommon for people who feel depressed to use alcohol or substances as a way to cope. However, alcohol can affect the brain in ways that worsen depression.

People who have difficulty coping with various life events may be more prone to developing depression. People who are low in extraversion and high in neuroticism have a higher risk of developing depression.

If you or a loved one have been feeling depressed and low, seek help as soon as possible. You can reach out to a mental healthcare provider or contact your primary care doctor for a diagnosis or referral.

Your healthcare provider will ask you a series of questions that will likely cover your symptoms, thoughts and feelings, and medical history. They may need to perform a physical or psychological exam, or conduct lab tests, in order to rule out other health conditions that can cause similar symptoms.

Your healthcare provider will determine whether or not your symptoms meet the diagnostic criteria for major depressive disorder, which include:

While depression is a serious condition, it can be treated. In fact, between 80% to 90% of people with depression respond well to treatment, and almost all patients get some relief from their symptoms.

It’s important to seek treatment for depression as soon as possible, because the earlier it is treated, the more effective the treatment can be. Ignoring the symptoms of depression and leaving it untreated can lead to self-harm or death.

Treatment for depression may involve medication, therapy, or brain stimulation. The treatment modalities chosen can depend on the severity of the depression and your individual needs.

Antidepressants are a type of medication that can help treat depression. They work by improving the balance of neurotransmitters in the brain. They are typically prescribed to treat moderate or severe cases of depression.

There are many different kinds of antidepressants, so you may need to try a few different types before you find the one that works best for you.

However, it’s important to note that antidepressants can take a few weeks or months to improve your mood, so you need to give the medication time to reach its full effect.

Psychotherapy, or talk therapy, can help treat depression. For mild cases of depression, your healthcare provider may recommend only psychotherapy, whereas for moderate to severe cases, a combination of medication and therapy may be recommended.

These are some of the types of therapy that can help treat depression:

You should expect to start feeling better after the first 10 to 15 sessions of therapy. The length of treatment can vary depending on how severe the depression is.

Certain medical procedures known as brain stimulation therapies can help with severe cases of depression that aren’t responding to medication or therapy. The different types of brain stimulation include:

These are some tips that can help you cope with depression:

Major depressive order, a type of depression, is a serious medical condition that is caused by a chemical imbalance in the brain. It is neither a character flaw nor a weakness, and can happen to anyone.

If you or someone you know are experiencing depression, it’s important to seek treatment for it. Treatment can reduce the symptoms, help you cope, and enable you to function on a day-to-day basis.