Depression, also referred to as clinical depression or major depressive disorder, is a medical condition that is classified as a mood disorder.1 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.2
At a Glance
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.
Symptoms of Major Depressive Disorder
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.3
These are some of the symptoms of major depressive disorder you may experience:1
- Feeling sad or low
- Having an “empty” mood
- Feeling anxious
- Feeling guilty or helpless
- Feeling worthless, hopeless, or pessimistic
- Feeling restless, frustrated, or irritated
- Losing interest in things you once enjoyed
- Avoiding your usual activities
- Having less energy and feeling fatigued
- Moving or speaking slowly
- Having difficulty paying attention, remembering, or making decisions
- Having difficulty sleeping, waking up too early, or oversleeping
- Experiencing unplanned changes in eating habits and weight
- Experiencing headaches, cramps, digestive issues, or other aches and pains that don’t have a clear cause and don’t get better with treatment
- Talking about death, having thoughts of suicide, or attempting self-harm
Types of Depression
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:3
- Major depressive disorder: This is a form of depression where the person experiences symptoms for over two weeks. The symptoms affect their ability to eat, sleep, work, and function.
- Persistent depressive disorder: Also known as dysthymia, this is a form of depression that lasts for over two years.
- Perinatal depression: This is a form of depression people experience during pregnancy (known as antepartum depression) and after pregnancy (known as postpartum depression).
- Premenstrual dysphoric disorder (PMDD): PMDD is a severe, disabling form of premenstrual syndrome (PMS) that can cause extreme mood swings.
- Depression with psychotic features: A person may have psychotic depression if they have depression as well as psychosis, which is a condition that can make it hard to distinguish between what’s real and what isn’t.
- Seasonal affective disorder (SAD): This is a form of depression that occurs in winter, when there is less natural sunlight.
- Bipolar disorder: While bipolar disorder is not technically a type of depression, it can cause periods of low moods with similar symptoms to major depression.
Causes of Major Depressive Disorder
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.4
The potential causes and risk factors for depression include:5
Biochemistry
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.6 Neurotransmitters like serotonin and dopamine do play an important role in mood, which is why antidepressant medications that affect neurotransmitter levels may be helpful.
Genetic Factors
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.7
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.8
Personal Medical History
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.9
Gender
Women may be twice as likely to develop depression than men.10 Factors contributing to this increased risk include hormonal differences, socialization differences, and greater life stress.
Life Events
Trauma, the death of a loved one, major life changes, and other upsetting events can cause depression.11 People who experience trauma in childhood have a higher risk of developing depression as adults.
Stress
Stress can affect you physically and mentally, and increase your risk of developing depression.12
Isolation
Lack of support and social isolation can increase the chances of developing depression. Unfortunately, social withdrawal is a common symptom of depression.
Medical Conditions
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.13
Medication
Some medicines can cause depression as a side effect. Some medications that can have depression as a side effect include:
- Anticonvulsants
- Antidepressants
- Corticosteroids
- Hormonal contraceptives
- Opioids
- Parkinson’s medications
- Proton pump inhibitors
- Stimulants
Substances
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.
Personality
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.14
Diagnosing Major Depressive Disorder
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:1
- Having a persistently depressed mood and lack of interest in activities
- Having five or more symptoms of depression
- Having symptoms every day, almost all day
- Having symptoms for over two weeks
- Being unable to function like you did before, due to the symptoms
Treating Major Depressive Disorder
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.15
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.3 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.
Medication
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.
Therapy
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:15
- Cognitive behavioral therapy (CBT): CBT can help you recognize unhelpful thought patterns contributing to depression. It can help you develop more positive thoughts and behaviors.
- Psychodynamic therapy: Psychodynamic therapy can help you explore and understand how factors from your past, such as traumatic events, may have played a role in the development of depression.
- Group therapy: This type of therapy is conducted in a group setting, rather than an individual setting. It can be helpful to interact with people who have similar experiences in a supportive environment.
- Couples or family therapy: Family therapy can help address issues within the family, whereas couples therapy can help partners work through issues together.
You should expect to start feeling better after the first 10 to 15 sessions of therapy.15 The length of treatment can vary depending on how severe the depression is.
Brain Stimulation
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:16
- Electroconvulsive therapy (ECT): ECT involves electrical stimulation of the brain. The procedure is painless and you won’t be able to feel the electrical impulses, but you will need to take a muscle relaxant and undergo brief anesthesia before each session.
- Repetitive transcranial magnetic stimulation (rTMS): rTMS is a noninvasive procedure that involves placing an electromagnetic coil near your forehead. The coil delivers a magnetic pulse that stimulates nerve cells in the brain. rTMS is performed on an outpatient basis and doesn’t require anesthesia.
- Vagus nerve stimulation (VNS): VNS involves implanting a device that sends pulses of electric energy to the brain, through the vagus nerve in the neck. You can think of it as a pacemaker for your brain. The device is inserted during a surgical procedure that may require an overnight stay in a hospital.
Coping With Major Depressive Disorder
These are some tips that can help you cope with depression:17
- Share your feelings with close friends and family members
- Understand that recovery may be gradual, so set realistic goals for yourself
- Postpone important decisions until you feel better
- Stay active and exercise regularly18
- Maintain a consistent routine
- Get enough sleep
- Eat a balanced, nutritious diet
- Avoid alcohol, nicotine, drugs, and medicines that have not been prescribed to you