What is depression?

One of the most common psychiatric disorders is major depressive disorder (MDD), usually referred to simply as depression.  Statistically speaking, there is a very high chance that either you, a family member, or a close friend will suffer from depression at some point in your life.  What is depression, and how common is it?
Video Activity

Watch the video below, in which a young woman describes what depression can feel like.  As you watch the video, make some notes on the symptoms of depression mentioned.                 
Symptoms of Depression

Symptoms of depression can be divided into four categories:  affective, behavioral, cognitive, and somatic.  Affective symptoms refer to changes in mood and emotion.  Behavioral symptoms, as the name implies, refer to changes in behavior.  Cognitive symptoms refer to changes in thought patterns.  Lastly, somatic symptoms refer to changes in the body.

  • Affective symptoms include feelings of sadness, guilt and worthlessness, and a lack of enjoyment of activities or the company of other people

  • Behavioral symptoms include passivity, a lack of initiative, and self harm / suicide attempts

  • Cognitive symptoms include recurring automatic negative thoughts, such as hopelessness and self-blame

  • Somatic symptoms include loss of energy, changes in sleep patterns (can either be insomnia or sleeping too much), and sudden changes in weight (can involve either dramatic weight gain or weight loss)

See the image below for the formal list of symptoms used to diagnose major depressive disorder in the DSM.  Note that at least 5 or the 9 symptoms (including at least one of the first two symptoms) must be present for two weeks or more to be formally diagnosed, and that the symptoms must cause a significant depress of distress or impairment.
Try it Out

Click the link below to take a depression quiz.  As you complete the quiz, make a note of which questions refer to affective, behavioral, cognitive and somatic symptoms.

If you think you may be depressed, do speak about it with a trusted friend, parent, teacher, or school counselor.  There is no reason to suffer in silence.

Depression Quiz
Prevalence Facts

A number of research studies have been carried out to estimate the prevalence of depression.  By combining the results from many different studies, we can make general conclusions about how common depression is.  Here is a summary of the key facts regarding the prevalence of depression:

  • In Western countries, around 15% of people will suffer from depression at some point in their lives

  • The rate of depression is approximately 2-3 times higher in females than in males.  Around 20-25% of women will become depressed at some point in their lives, while the rate for men is 7-12%

  • Rates of depression are higher in lower socioeconomic groups, young adults, and people who are divorced

  • On average, an episode of depression lasts from around 3-4 months

  • Unfortunately, 80% of people who experience a depressive episode will go on to experience at least one more depressive episode at some point.  The average number of depressive episodes across a person's life is 4.

  • In approximately 12% of cases, depression becomes a chronic condition, meaning that it does not resolve itself after a few months.  In these cases, the average length of depression is 2 years

The statistics above are largely drawn from research in Western countries.  You may be wondering whether these statistics also apply to the rest of the world.  Do people from different cultures get depressed at the same rate?  Read the study below to find out
Research: Weisman et al

Aim: To investigate the prevalence of depression in different countries


  • This study was carried out in 10 countries across the world, including a range of different cultures - the United States, Canada, Puerto Rico, France, West Germany, Italy, Lebanon, Taiwan, Korea, and New Zealand.

  • Participants in each country were randomly selected using telephone registries.  A trained interviewer would call the people selected and interview them about their mental health history.  A total of 38,000 participants were interviewed


  • Rates of depression varied tremendously in different countries.  The lifetime prevalence of depression was only 1.5% in Taiwan, but as high as 19% in Beirut, Lebanon

  • Surprisingly, the rate of depression in Paris (16.4%) was almost as high as that of Beirut, despite the fact that Beirut had just experienced 15 years of brutal civil war

  • In spite of the large variation in depression rates, some patterns were noticed across the world.  In each country, the rate of depression in women was 2-3 times higher than in men.  And people who were separated or divorced had much higher rates of depression than people who were currently married


  • Depression is a universal disorder, and some risk factors for depression - like being female, or having a divorce - are common across the world

  • On the other hand, people from some countries seem to suffer from much higher rates of depression than others, for reasons that are not certain


  • This study had an impressive number of participants, as well as a strong random sampling method, so the findings can be generalized to the population of each country

  • Because this study was carried out in multiple languages, there is always the risk that translation between languages may not be completely precise

  • Although the study found very different rates of depression in different countries, it does not explain why people in some countries seem to be more likely to become depressed
Why does prevalence vary?

As research by Weisman suggests, the prevalence of depression varies a great deal between countries.  A number of different explanations have been offered to explain this variation.  The explanations fall into one of two broad categories:

Firstly, there may be real differences in rates of depression - meaning that, in some countries, people are truly more likely to get depressed.  Reasons for this could include:

  • Different socioeconomic conditions - In some countries, many people struggle with poverty, constant stress, the threat of violence or war, or long periods of unemployment.  Living in such difficult conditions may lead to higher rates of depression than living in stable, safe and prosperous countries

  • Different rates of urbanization - As countries develop economically, more people tend to move out of villages and small towns, and into crowded, stressful cities.  Some researchers believe that urban living is linked to higher rates of depression, since city dwellers are more likely to be stressed and socially isolated, living busy, chaotic lives in the midst of thousands of anonymous strangers

On the other hand, perhaps a great deal of the difference in prevalence rates can be explained by differences in how often depression is reported, rather than any real difference in the actual rate.  Some reasons why people in some countries may be less likely to report depression include:

  • Differences in cultural stigma - In some countries, mental illness is still considered a shameful topic, one which is kept hidden behind closed doors.  In these countries, more people suffer depression in secret, without ever being diagnosed.  If they do seek help, they may report physical symptoms only (like being unable to sleep, or muscle pain), and hence may never be given the correct diagnosis

  • Differences in how depression is diagnosed - In some countries, psychiatrists may be more likely to diagnose depression than others, depending on the culture of mental health treatment.  The line between mild depression and ordinary sadness is somewhat blurry, and so rates of depression could vary because of different mental health training and practices

  • I can describe the affective, behavioral, cognitive and somatic symptoms of depression

  • I can discuss the prevalence of depression, describing which demographic factors are associated with higher risk of depression

  • I can describe the aim, procedure, findings and conclusion of Weisman's study on the prevalence of depression.  I can also evaluate the study

  • I can compare and contrast different explanations for cultural variation in the prevalence of depression

Quiz Yourself!

1.  All of the following are behavioral symptoms of depression, except for _____

(a) Acts of self-harm

(b) Thoughts of suicide

(c) Passivity

(d) Lack of motivation

2.  Which of the following groups is NOT at a higher risk of depression?

(a) Women

(b) Children

(c) Divorced people

(d) Poor people

3.  According to Weisman's reseach, the place with the lowest rate of depression is ___

(a) Taiwan

(b) Korea

(c) Paris

(d) Canada

4.  Paris has one of the highest rates of depression in the world.  What could explain this?

(a) Cultural, economic and social factors in Paris have created an epidemic of depression

(b) A decrease in stigma in Paris has encouraged more people to seek help for mental illness

c) Both A and B are possible explanations

d) Neither A nor B are possible explanations

5.  You are a young adult experiencing an episode of depression.  Which statement is false?

(a) On average, your depression will last for approximately 2 years

(b) You will likely become depressed again at some point in your life

(c) You are at a higher risk of suicide

(d) You will probably start feeling better within a few months

1 - B, 2 - B, 3 - A, 4 - C, 5 - A