Patient Basics: Major Depression

Major depression, also called clinical depression or major depressive disorder, is a medical condition that brings a low mood or a loss of interest in almost everything for at least two weeks. It affects sleep, appetite, energy, focus and how you see yourself. It’s common, and most people get better with talk therapy, medicine or both. If you’re thinking about suicide, call or text 988 now.

Key points

• Major depression lasts most of the day, nearly every day, and gets in the way of work, school or relationships.
• Trouble focusing and making decisions is a common symptom.
• Genes, stress, hormones, other illnesses and some medicines can all play a part. Sometimes there’s no clear trigger.
• Talk therapy and antidepressants both work. Many people do best with both.
• Antidepressants take several weeks to work fully. Don’t stop them suddenly.

Symptoms of major depression

Doctors diagnose major depression when five or more of these last at least two weeks, and at least one is a low mood or loss of interest:

• Feeling sad, empty, hopeless or, especially in teens, irritable
• Losing interest or pleasure in things you used to enjoy
• Sleeping much more or much less than usual
• Eating more or less, with weight gain or loss
• Feeling tired or drained of energy
• Moving or speaking slowly, or feeling restless
• Feeling worthless or guilty
• Trouble thinking, concentrating or deciding
• Thoughts of death or suicide

Depression can also cause headaches, aches and stomach problems. An episode can be mild, moderate or severe.

What causes major depression

• Family history. Depression often runs in families.
• Brain changes. The brain circuits that manage mood, stress and reward work differently during depression.
• Stress and loss. Grief, money or job troubles, loneliness, trauma or abuse can bring it on.
• Other health problems. Thyroid disease, chronic pain, heart disease, stroke, cancer, diabetes and Parkinson’s disease raise the risk.
• Hormone changes. Depression can start during pregnancy or after a baby is born, around menopause, or in the days before a period.
• Medicines and substances. Steroids such as prednisone, interferon and some hormonal medicines can affect mood in some people, and so can alcohol and drugs.

If your mood dropped after starting a medicine, tell the prescriber. Don’t stop it on your own.

How it’s diagnosed

A primary care doctor or mental health professional will ask about your mood, sleep, energy, thoughts and daily life. You may fill out a short questionnaire. Blood tests can check for thyroid problems, anemia and low vitamin B12. Your doctor will also ask about past periods of very high energy or little need for sleep, because those can mean bipolar disorder, which is treated differently. They’ll ask about alcohol and drug use, too.

How major depression is treated

Talk therapy

Cognitive behavioral therapy (CBT) helps you notice and change thought patterns that keep depression going. Behavioral activation gets you back into activities that bring meaning or pleasure. Interpersonal therapy focuses on relationships and life changes. Therapy usually means weekly sessions for a few months, in person or by video.

Antidepressants

Common first choices include SSRIs such as sertraline, escitalopram and fluoxetine, and SNRIs such as venlafaxine and duloxetine. Bupropion and mirtazapine are other options. No single drug is best for everyone. Your doctor will consider side effects, your other health conditions and what has worked for you or your family before.

• Some improvement often shows in 2 to 4 weeks. Full effect takes 6 to 8 weeks or more.
• Early side effects can include nausea, headache, sleep changes and sexual problems. Many ease within a few weeks.
• Keep taking the medicine for at least 6 to 12 months after you feel well, to lower the chance of relapse.
• Stopping suddenly can cause dizziness, flu-like feelings and a return of symptoms. Your doctor can help you taper off slowly.
• In people under 25, antidepressants can raise suicidal thoughts in the first weeks. Close follow-up is important.

If the first treatment doesn’t help

Many people need to try more than one option. Doctors may change the dose, switch medicines, add a second medicine, or add therapy. For depression that hasn’t improved after two or more treatments, options include esketamine nasal spray (Spravato), given in a clinic, and transcranial magnetic stimulation (TMS), which uses magnetic pulses through the scalp. Electroconvulsive therapy (ECT), done under anesthesia, works well for severe depression. For depression after childbirth, a short course of zuranolone pills is an option.

Daily habits

Regular exercise, a steady sleep schedule, time with people you trust, and less alcohol all help treatment work. For depression that comes back each winter, a light therapy box may help.

Recovery and staying well

Without treatment, an episode often lasts six months or more. With treatment, most people feel better within weeks to a few months. About half of people who have one episode have another, so learn your early warning signs, such as poor sleep or pulling away from friends, and get help early if they return.

When to get help

• You’ve felt down or lost interest most days for two weeks
• It’s hard to work, study or take care of yourself
• You’re drinking or using drugs to cope. The SAMHSA helpline (1-800-662-4357) is free and open all day, every day.

Get help right away if you’re thinking about suicide or harming yourself. Call or text 988 (Suicide & Crisis Lifeline), or call 911. If someone you know talks about suicide, stay with them and help them call.

Common questions about major depression

Why do I feel depressed even though nothing’s wrong?

Major depression doesn’t need a reason. It can start when life is going well, because genes, brain chemistry, hormones and health problems all play a part. Feeling low without a clear cause doesn’t mean you’re imagining it or being ungrateful. It’s a sign to talk with a doctor.

Can depression make it hard to focus?

Yes. Trouble concentrating, remembering things and making decisions is one of the main symptoms. Reading, following a conversation or finishing work can feel much harder. Focus usually improves as the depression is treated. Tell your doctor if it doesn’t, because sleep problems or other conditions may be adding to it.

What is the best medicine for major depression?

There’s no single best antidepressant. Most work about equally well on average, but people respond differently. Doctors often start with an SSRI such as sertraline or escitalopram, then adjust based on side effects and results. The best one for you is the one that helps and that you can keep taking.

How do antidepressants make you feel?

The goal is to feel more like yourself, not artificially happy. Sleep, energy and appetite often improve first, and mood lifts gradually over weeks. Some people feel emotionally flat or numb. If that happens, or side effects bother you, tell your doctor. A dose change or a different medicine often helps.

Can depression get worse around your period?

Yes. Many people with depression notice it worsens before their period. Some have premenstrual dysphoric disorder (PMDD), where severe low mood, irritability or anxiety starts in the week or two before a period and eases soon after it begins. Tracking your mood for a few cycles helps your doctor choose treatment.

Questions to ask your doctor

• How severe is my depression?
• Should I start with therapy, medicine or both?
• What side effects should I watch for?
• How long until I should feel better, and what if I don’t?
• Could a health problem or one of my medicines be playing a part?

Learn more

• Depression (National Institute of Mental Health)
• Depression (MedlinePlus, U.S. National Library of Medicine)

This guide is general information and doesn’t replace advice from your own doctor. Last updated October 2026.