Sadness, grief, and even passing feelings of hopelessness or despair are part of the human experience. Most people experience these feelings from time to time, but they’ll generally improve within a few days, or as the situation changes.

Major depression, or major depressive disorder, however, involves a low or sad mood that persists for 2 weeks or longer. You might also notice declining energy, loss of appetite, feelings of emptiness or emotional numbness, and a loss of interest in the things you used to enjoy.

Untreated depression can affect physical and emotional well-being, as well as personal life and relationships.

But support from a mental health professional can make a big difference in your symptoms, and you have plenty of options for treatment, including therapy, medication, and complementary treatments, like acupuncture and hypnotherapy.

Several types of depression exist, and their symptoms may show up in slightly different ways.

Major depressive disorder

When people refer to “depression,” they’re often talking about major or clinical depression.

The National Institute of Mental Health (NIMH) estimates that 19.4 million adults, or 7.8 percent of all adults in the United States, had at least one episode of major depression in 2019.

Episodes of major depression were more common among:

  • women (9.6 percent, compared to 6 percent in men)
  • people between the ages of 18 and 25 (15.2 percent)
  • people who describe themselves as being of two or more races or ethnicities (13.7 percent)

Persistent depressive disorder

Persistent depressive disorder, or dysthymia, is a type of chronic depression that lasts 2 years or longer. It generally involves milder feelings of sadness and hopelessness, along with other depression symptoms.

The mood changes associated with persistent depression may be less severe, but they can still cause plenty of distress.

Estimates suggest 3 percent of people in the United States may have this type of depression.

Bipolar disorder

Not everyone who lives with bipolar disorder will experience an episode of depression, but many do:

  • Bipolar I involves episodes of mania, but it may also involve episodes of depression.
  • Bipolar II involves episodes of depression and hypomania.

Research from 2018 suggests around 1 percent of people develop bipolar I at some point in life, though estimates vary.

According to a 2015 review of 25 population- and community-based studies:

  • Lifetime prevalence of bipolar I was 1.06 percent, and 0.71 percent of people had bipolar I in a given year.
  • Lifetime prevalence of bipolar II was 1.57 percent, and 0.50 percent of people had bipolar II in a given year.

Learn more about the types of bipolar disorder.

Seasonal depression

Major depressive disorder with seasonal pattern, sometimes called seasonal affective disorder, involves changes in mood that happen alongside changes in the seasons. For many people, this type of depression begins in autumn and lasts through winter, but some experience seasonal depression symptoms in spring and summer.

The American Psychiatric Association notes that around 5 percent of American adults experience seasonal depression, with symptoms that generally linger for around 40 percent of the year.

Seasonal depression more commonly affects:

  • women
  • young adults
  • people living at higher altitudes

Symptoms of seasonal depression also return each year for almost 70 percent of people living with the condition, according to 2021 research.

Postpartum depression

Temporary feelings of sadness and fatigue, along with shifts in mood, are very common after childbirth. These “baby blues” can have a range of causes, including:

  • hormonal changes
  • lack of sleep
  • pressures of caring for a newborn

But if these mood changes intensify, or persist for more than a week or two, you could have major depressive disorder with peripartum onset, or postpartum depression, as it’s commonly called.

According to 2021 research, between 6.5 and 20 percent of women develop postpartum depression after giving birth, and the condition more commonly affects new parents who:

  • are adolescents
  • live in urban areas
  • deliver premature babies

Postpartum depression can lead to social withdrawal, loss of appetite, and unwanted emotions. It can also affect your relationship with your baby.

It’s important to note that this condition doesn’t develop because of anything you did or didn’t do as a parent.

Learn more about getting support.

Psychotic depression

Major depressive disorder with psychotic features describes depression that involves psychosis, or hallucinations, delusions, or paranoia.

Research on depression with psychotic features remains fairly limited, in comparison to research on other types of depression. But some experts believe this subtype is more common than previously believed.

According to 2021 research, depression with psychotic features affects:

  • about 4 in every 1,000 adults
  • between 14 and 30 adults over age 60

The same review notes that symptoms of psychosis develop during an episode of depression for:

  • between 10 and 19 percent of adults in community samples
  • 25 to 45 percent of adults receiving inpatient care
  • 24 to 53 percent of older adults receiving inpatient care

Depression is common.

According to estimates from the World Health Organization (WHO), about 280 million people worldwide have depression, including 5 percent of the world’s adults and 5.7 percent of adults above the age of 60.

The NIMH estimates that 19.4 million adults in the United States had at least one major depressive episode in 2019. This represents 7.8 percent of the U.S. adult population.

Yet since many people with depression don’t get help for their symptoms, the actual number of people living with depression may be higher:

  • Research from 2021 suggested almost 60 percent of people who have depression don’t seek professional support, in part due to the stigma of depression.
  • The WHO also notes that over 75 percent of people living in low-income or middle-income countries never get treatment for depression, due to treatment barriers.

You may have depression if feelings of sadness or emptiness linger through most of each day, for longer than 2 weeks. Other key mental and emotional symptoms include:

  • unusual irritability or difficulty managing anger
  • changes in energy, including restlessness, fatigue, or a sense of being slowed down
  • loss of enjoyment in your usual interests, including hobbies or spending time with friends and loved ones
  • a tendency to ruminate on regrets and fears, mistakes you believe you’ve made, or other dark thoughts
  • brain fog, or difficulty concentrating and making decisions
  • thoughts of death or suicide

Depression can cause physical symptoms, too, including:

In children and adolescents, depression often involves:

  • low self-esteem
  • guilt
  • unusual irritability or tearfulness
  • physical symptoms, including stomachaches and headaches
  • difficulty concentrating
  • frequent absences from school

In older adults, unexplained memory loss, sleep problems, or withdrawal could suggest depression, but they can also suggest Alzheimer’s disease or other types of dementia.

Learn more about the signs of depression in older adults.

Symptoms of depression can range from mild to severe. The 2019 National Health Interview Survey asked adults about their symptoms over the past 2 weeks and found that:

  • 2.8 percent of adults had severe symptoms
  • 4.2 percent had moderate symptoms
  • 11.5 percent had mild symptoms

Experts believe depression develops in response to a combination of factors, including brain chemistry, hormones, and genetics. In other words, there’s no single cause of depression.

Other risk factors for depression include:

  • A history of trauma or abuse. A 2015 study found that 75.6 percent of 349 people with chronic depression had a history of childhood trauma.
  • A history of other mental health conditions. Post-traumatic stress disorder, anxiety disorders, and obsessive-compulsive disorder have all been linked to depression.
  • Chronic conditions. Estimates suggest between 9.3 and 25 percent of people living with chronic conditions, such as diabetes or chronic pain, also have depression.
  • Substance use disorders. Anywhere from 12 to 80 percent of people with a substance use disorder experience depression at the same time.
  • Family history. According to the new edition of the “Diagnostic and Statistical Manual of Mental Disorders (DSM-5),” people with a family history are 2 to 4 times as likely to develop depression.

Learn more about potential causes and risk factors for depression.

A diagnosis of major depression generally requires:

If you or someone you know has symptoms of depression, a good next step involves connecting with a mental health professional.

Symptoms that don’t exactly align with the criteria above could still suggest certain subtypes of depression, so it’s always important to reach out.

Tell them about all of your symptoms, even those that don’t seem relevant, since a detailed picture of your symptoms can help them make the most accurate diagnosis.

The main treatments for depression include:

According to the American Psychiatric Association, a combination of antidepressants and therapy is, on average, more effective. But both treatments have about the same effectiveness when used alone.

Your therapist may recommend therapy or a combination of medication and therapy, depending on your symptoms and personal preference.

When it comes to depression treatment, it’s important to find a treatment that works for you. If you feel comfortable with the approach, you’re more likely to continue treatment, which can lead to more improvement in your symptoms over time.

A few facts about treatment:

  • Studies suggest between 40 and 60 percent of people taking antidepressants for moderate or severe depression notice improved symptoms after 6 to 8 weeks. In contrast, between 20 and 40 percent of people taking a placebo notice similar improvements.
  • Evidence-based therapy for depression, such as cognitive behavioral therapy, leads to remission of symptoms about 30 to 40 percent of the time.
  • Studies suggest about 23 percent of people taking antidepressants have a relapse of depression symptoms within a year or two. To contrast, nearly half of those taking placebos have a relapse within the same timeframe.

Depression doesn’t just affect emotional well-being. It can also have a significant impact on your daily life, personal relationships, and physical health.

Living with depression can also increase your chances of experiencing suicidal thoughts. In the United States alone, depression leads to about 40,000 deaths by suicide each year.

Depression can also play a part in other unwanted health and life outcomes, including:

  • headaches and other chronic aches and pains
  • substance use disorders
  • problems at work or school
  • difficulties in relationships with family, friends, and romantic partners
  • social withdrawal and loneliness
  • increased risk of other health and mental health conditions
  • self-harm

Getting support from a therapist can go a long way toward preventing these complications.

While you can take steps to lower your risk of developing depression, experts have yet to find a way to prevent it completely. That said, learning to recognize the signs of depression and knowing how to get help when needed can help you address symptoms early, before they get worse.

Statistics can absolutely have value, of course, but they may not always seem relevant to your specific circumstances. Maybe you have no family history of depression, for example, or any other key risk factors. Perhaps you experience symptoms in an uncommon pattern, like depression that worsens in summer.

No matter what symptoms you experience or how they show up, a trained therapist can help you begin to explore possible causes and offer guidance on effective treatments.