Major Depressive Disorder: Causes, Symptoms, and Treatment
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Major Depressive Disorder?
A psychiatrist, a doctor who treats mental health conditions, or a primary care doctor often diagnoses and treats major depressive disorder. A psychologist can also help. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is major depressive disorder?
Major depressive disorder is also called major depression or clinical depression. It can cause severe symptoms that affect how a person feels, thinks, and handles daily activities, such as sleeping, eating, or working.
Everyone feels sad or low sometimes, but these feelings usually pass. Major depression has a low mood or loss of interest. It lasts most of the time for at least 2 weeks and gets in the way of daily life.
Symptoms
Common signs and symptoms of depression include:
- A sad, anxious, or empty mood that lasts.
- Feeling hopeless, guilty, worthless, or helpless.
- Loss of interest or pleasure in hobbies and activities.
- Trouble concentrating, remembering, or making decisions.
- Changes in appetite or unplanned weight changes.
- Thoughts of death or suicide.
Not everyone who is depressed shows all these symptoms. A child may seem more irritable than sad. In teens, problems with school, behavior, or alcohol or drug use can all be signs.
Causes and who gets it
Health care providers do not know the exact causes of depression. Chemical changes in the brain are believed to be responsible. This may be due to your genes. It may also be triggered by stressful events. A mix of both is more likely.
Some types of depression run in families. Other types occur even if you have no family history of the illness.
Depression may be brought on by:
- Alcohol or drug use.
- Certain medical problems, such as an underactive thyroid, cancer, or long-term pain.
- Stressful life events, such as the death of someone close to you, divorce, or childhood abuse or neglect.
Anyone can develop depression, including children and teens. Women are diagnosed with depression more often than men. Hormone changes can bring on a depressive episode in some people. They happen with pregnancy, after childbirth, with the menstrual cycle, and at menopause.
How doctors diagnose it
To be diagnosed, a person must have symptoms most of the day, nearly every day. They must last at least 2 weeks. One symptom must be a low mood or a loss of interest or pleasure in most activities.
Your provider will ask about your medical history and symptoms. Some medicines and illnesses can cause the same symptoms as depression. Examples are viruses and thyroid problems. A provider can rule these out with an exam, an interview, and lab tests.
Treatment
Depression can be treated. Treatment typically involves talk therapy (also called counseling), medicine, or both.
For milder depression, therapy is often tried first, with medicine added later if needed. People with moderate or severe depression usually get medicine as part of the first treatment plan.
Evidence-based talk therapies include cognitive behavioral therapy and interpersonal therapy. Cognitive behavioral therapy helps people change unhelpful thoughts and behaviors.
Antidepressants are medicines often used to treat depression. They change how the brain produces or uses certain chemicals involved in mood or stress. They take time to work, usually 4 to 8 weeks. Do not stop your medicine or change the amount without talking to your provider. Follow your doctor's instructions.
Children, teens, and young adults should be watched closely for suicidal behavior. This matters most in the first few months after starting depression medicine.
Brain stimulation therapy is an option when other treatments have not worked. It uses electricity or magnetic waves on the brain.
Talk to a health care provider before using vitamin D, St. John's wort, or other supplements. St. John's wort can change the way other medicines work in your body, including antidepressants.
When to see a doctor
If you have signs of depression that do not go away, talk to a health care provider.
If you feel your medicine is making you worse or causing new symptoms, such as confusion, tell your provider right away.
If you are thinking about harming yourself, call or text 988 (the Suicide and Crisis Lifeline) right away.
You can also call 911 or go to the emergency room right away if you are thinking about hurting yourself or others. If someone you know has attempted suicide, call 911 right away. Do not leave the person alone.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A direct primary care doctor can review your symptoms, check for other causes, and follow up. They can also help you reach a mental health professional.
Common questions
Is major depression the same as feeling sad?
No. Everyone feels sad or low sometimes, but these feelings usually pass. Depression is different. It can cause severe symptoms that affect daily activities.
How long do antidepressants take to work?
Antidepressants usually take 4 to 8 weeks to work. Problems with sleep, appetite, and concentration often improve before mood lifts.
Can major depression be treated?
Yes, depression can be treated. The choice depends on how severe it is and what you and your provider prefer.
Sources
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
