Major depressive disorder is another name for depression. It can cause a persistent low mood, sleep disturbances, difficulty focusing, a loss of motivation, and other symptoms.

A person with major depressive disorder (MDD) or clinical depression — will experience a persistently low mood for 2 weeks or more and a loss of interest in activities they usually enjoy.

Individual symptoms may include sleep problems, fatigue or loss of energy, changes in appetite, or difficulty concentrating.

There are different types of depression, including major depressive disorder with psychotic features.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects if it’s safe to do so.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Find more links and local resources.

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Symptoms of major depressive disorder can include anxiety, sleep problems, irritability, and feelings of hopelessness.

There are several types of major depressive disorder, and each has slightly different symptoms that may occur at certain times in a person’s life.

Types of major depressive disorder include:

  • Major depression with seasonal pattern: A person may experience this form of depression in winter months due to a lack of sunlight.
  • Major depressive disorder with peripartum onset: Up to 6% of women will experience an episode of depression during pregnancy or in the first year after giving birth.
  • Major depressive disorder with psychotic features: A person experiences delusions or hallucinations alongside other symptoms of depression.

For a diagnosis of major depressive disorder, a person will have had some of the following symptoms every day for at least 2 weeks:

  • changes in sleep patterns
  • persistent sad or low mood
  • changes in appetite
  • reduced motivation
  • unexplained aches and pains
  • thinking about or attempting suicide
  • lack of interest in usual pastimes
  • difficulty focusing

The type, length, and severity of symptoms vary between individuals.

When diagnosing depression, a doctor will use a questionnaire to evaluate symptoms as defined by the Diagnostic and Statistical Manual of Mental Disorders.

Clinical depression can affect anyone, but common symptoms change slightly between age groups. There are separate questionnaires for children and adults.

A diagnostic questionnaire asks how symptoms have affected the person over the previous 2 weeks.

There are five ways a person can respond to each symptom, ranging from no effect to causing problems almost every day.

An evaluation for depression might include questions about other psychological features, including:

  • anger
  • mania
  • anxiety
  • somatic symptoms
  • suicidal ideation or attempt
  • psychosis
  • sleep problems
  • repetitive thoughts and behaviors
  • substance use

Psychiatric domains for children and teens also include irritability and attention. Adult domains include personality function, memory, and dissociation.

Questions about symptoms are categorized under psychiatric domains.

Children and teens (age 6–17)

For those aged 6–17, an assessment would ask about some of the following symptoms:

  • experiencing physical aches or pains
  • frequently concerned about health or feeling unwell
  • sleeping problems
  • difficulty paying attention
  • having less fun than normal
  • feeling sad or depressed for several hours
  • becoming easily annoyed or irritated
  • starting more projects or taking more risks
  • having lots of energy with unusually little sleep
  • feeling nervous, scared, or anxious
  • avoiding doing things because they cause nervousness
  • hearing voices when no one is there
  • having a vision while awake
  • thinking of self or others doing something bad or having something bad happen
  • frequently feeling an urge to check on things
  • feeling a need to do something in a specific way to prevent anything bad from happening

An evaluation might also ask if the child has engaged in any of the following risky behaviors:

  • consumed alcohol
  • smoked, “snuffed,” or chewed tobacco
  • used drugs, e.g., cannabis, ecstasy, cocaine
  • taken medicine without a prescription
  • mentioned thoughts of suicide

A thorough evaluation will also ask if the child has ever attempted suicide.

Adults (18+)

When evaluating adults, specific questions will inquire whether the person has experienced symptoms in the previous week. The evaluation will also inquire as to the duration and intensity of these experiences:

The questions focus on how often a person has experienced these symptoms in the past week:

Symptoms include:

  • experiencing a lack of interest or pleasure in activities
  • feeling low, depressed, or hopeless
  • feeling irritated, grouchy, or angry
  • sleeping less but lots of energy
  • starting projects and taking more risks than normal
  • feeling nervous, anxious, scared, or on edge
  • feeling frightened or panicked
  • avoiding situations that cause anxiety
  • experiencing physical aches or pains with no known cause
  • feeling others are not taking the person’s illnesses seriously enough
  • considering self-harm
  • hearing things that others cannot
  • feeling others can hear their thoughts or vice versa
  • having problems sleeping
  • experiencing difficulty with orientation or memory
  • having recurring unpleasant thoughts, images, or urges
  • feeling the drive to complete mental or physical acts repeatedly
  • experiencing a separation from self, body, memory, or surroundings
  • feeling confused about self or what to get out of life
  • feeling distant from others
  • consuming more alcohol than usual
  • smoking, “snuffing,” or chewing tobacco
  • taking drugs or medication without a prescription

Older adults

As people get older, they may develop dementia and other neurological conditions. These can cause symptoms that resemble those of depression.

For this reason, doctors may find it challenging to diagnose depression in older adults.

Depression may develop with time, or an event or a combination of factors may trigger it. According to the National Institute of Mental Health (NIMH), some possible causes include.

Genetics, biology, and environment

  • Genetics: Like other mood disorders, genetics can cause clinical depression. People are more prone to the disorder if members of their family experienced it.
  • Biology: According to a 2018 article, changes in brain structure can occur as a person ages. This may increase the risk of depression.
  • Environment: Environmental factors — such as trauma or a significant loss — may trigger stress, anxiety, and depression in people who have genetic features that increase their risk.

Brain chemistry

Research suggests that in some people, a chemical imbalance in the brain causes depression.

According to the National Alliance on Mental Illnesses (NAMI), during depression, the brain’s pituitary gland and hypothalamus respond differently to hormone stimulation, and activity in the frontal lobe of the brain may also decrease.


The Office on Women’s Health (OWH) state that hormonal changes increase the risk of clinical depression, particularly in females.

The risk may be higher:

Changes in the balance of the hormones progesterone or estrogen can affect the likelihood of depression, according to the OWH.

Medical illness

An article in the Chonnam Medical Journal indicates that depression can start after a person experiences a physical condition, such as a stroke, heart attack, or cancer.

The article notes that this is common if the illness has a high mortality rate or causes significant changes to a person’s lifestyle.

Treating depression may involve lifestyle changes, therapy, medication, or a combination of strategies.


Depending on the person’s symptoms, a doctor may prescribe:

There are different types of antidepressants. It usually takes 2–4 weeks before results start to show.

If a person’s symptoms have not reduced after trying at least two different types of antidepressant medication, a doctor may prescribe the nasal spray esketamine.

The Food and Drug Administration (FDA) have recently approved esketamine for a person to use alongside antidepressants.


Psychotherapy is a key strategy for treating depression.

NIMH indicate that there are many types of psychotherapy, including:

  • counseling to address a specific issue, such as bereavement
  • cognitive behavioral therapy, which helps a person understand how their thinking can affect their behavior and mood

Some people find that depression resolves after a few months of attending psychotherapy, while others need treatment for several years.

Learn more about the different types of psychotherapy here.

Brain stimulation therapy

Brain stimulation therapy techniques may help if other approaches are not effective.

Options include:

These methods can help people whose symptoms have not responded to other treatments.

Lifestyle changes

A healthful, active lifestyle may help a person manage depression. According to a 2019 review, exercising may prevent depression from recurring, but scientists need to conduct more studies to support this.

Researchers are still unsure exactly how much exercise a person should do to prevent symptoms of depression. This is because most exercise guidelines aim to keep the body physically fit, with less focus on the mind.

Many factors increase the risk of depression, including:

  • genetic factors
  • experiencing major life changes
  • trauma
  • work-related and other types of stress
  • physical illness and recovery
  • the use of certain medications
  • insulin resistance

Depression can affect a person’s physical, social, and mental well-being. It can lead to challenges in many areas, including:

  • relationships
  • work and education
  • finances

In some cases, depression can lead to thoughts of suicide or self-harm, and even suicide attempts.

The family and friends of a person with depression can support them by learning more about their condition and helping them follow their treatment plan.

A person should seek medical attention if they notice symptoms of depression, such as a low mood that lasts for 2 weeks or more.

For many, seeking help can feel intimidating. However, depression is a widespread health problem, and a doctor will be able to suggest treatment strategies. Not seeking treatment can lead to further complications.

Depression affects people differently. With treatment, some people find it resolves within weeks or months. Others may need treatment for several years.

It can take time to find a treatment plan that works, but many people find their symptoms respond well to a combination of therapy and medication.

It is not always possible to prevent depression, but when a person knows their triggers and can recognize when an episode starts, it may be easier to take action.

As soon as a person notices the signs and symptoms of depression, they should seek medical help. Starting treatment early can help prevent depression from becoming severe.

According to NIMH, major depressive disorder is one of the most common mental illnesses in the United States. It can have a severe impact on daily life.

Treatment plans may include therapy, medication, and lifestyle measures.

A doctor can help each individual to find a strategy that works best for them.