Depression is a common psychiatric disorder in which a person experiences low moods and loses interest in daily or leisurely activities.
What Is Depression?
Depression 1 is a mental disorder marked by persistent sadness and diminished interest in previously enjoyed activities, along with other symptoms that interfere with daily functioning.
It exists on a continuum of severity—ranging from episodes of mild depression to severe and persistent depression that can have a major impact on a person’s quality of life and if left untreated, can even result in suicide.

Major depression or major depressive disorder is the most common type of depression, occurring in approximately 280 million people 2 around the world.
Sadness Vs. Depression
Sadness is a common human emotion and a natural reaction to pain or things that upset us. All of us feel sad occasionally. It is a temporary feeling that usually fades away with time.
Depression, on the other hand, comprises a range of other symptoms along with a feeling of sadness that persists for days. A person with depression usually feels an aversion to activity and may have problems concerning sleep and appetite as well.
Unlike normal sadness, depression can severely impair your ability to carry out daily activities and affect your relationships too. Depression is best managed with professional help like therapy and medication.

Case Example
Sheena (a 30 year old woman) had not been her usual self for the past couple of weeks. She was constantly feeling tired and spent most of her time sleeping in her room.
She was also beginning to lose interest in things that she liked doing before, such as reading and gardening. Her husband couldn’t understand what was going on with her and kept asking her to get it together.
But in the following days, Sheena became more and more distracted, and could hardly make proper conversation with her spouse and children.
She did not even react when her son said something funny that would usually make her crack up. It seemed as though she was lost in her own thoughts throughout the day.
As another week went by, her family and friends noticed that she was looking thinner than before. She began to avoid going out and meeting people and was not showering for days. Out of increasing concern, her husband decided to book her an online consultation with a psychologist.
It turned out that Sheena was actually suffering from a depressive episode.
Symptoms Of Depression
The symptoms 3 of depression can be categorized into two groups:
A. Psychological symptoms
The psychological symptoms 4 of depression include:
- Sad mood throughout the day
- Loss of interest in almost all activities
- Inability to make decisions
- Lack of concentration
- Pessimism
- Feelings of guilt, shame, and/or worthlessness
- Recurrent thoughts about (and sometimes attempts at) ending life
B. Somatic symptoms
The somatic symptoms of depression include:
- Fatigue or tiredness
- Changes in appetite
- Unintentional weight loss/ gain
- Extreme agitation or slowing of movements
- Sleep disturbance
- Body ache and pain
Prevalence
Depression is a debilitating mental disorder that affects an estimated 350 million 5 people of all ages worldwide.
Studies 6 reveal that the average lifetime and 12-month prevalence estimates of clinical depression are 14.6% and 5.5% in high-income countries and 11.1% and 5.9% in low- to middle-income countries. It is also found that women tend to suffer more from depressive symptoms, compared to men.
Diagnosis
According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), five or more of the main symptoms need to be present for at least a period of two weeks for a person to be diagnosed with a depressive episode. Moreover, the symptoms should not be a result of substance abuse or any other medical illness.
For an accurate diagnosis of depression, a mental health professional usually takes a detailed interview of the patient, and conducts certain psychometric tests.
Some examples include:
- The Beck Depression Inventory (BDI 7)
- The Patient Health Questionnaire (PHQ 8)
- Hamilton Depression Rating Scale (HAM-D 9)
- Children’s Depression Inventory (CDI), etc.
Certain medical tests, such as thyroid tests and blood hemoglobin tests may also be recommended in order to rule out any other causes for the symptoms.
Types Of Depression
Clinical depression can be of several types 10. The major types include the following:
- Major depressive disorder (MDD) [Read more]
- Persistent depressive disorder (Dysthymia) [Read more]
- Disruptive mood dysregulation disorder (DMDD) [Read more]
- Seasonal affective disorder (SAD) [Read more]
- Bipolar disorder [Read more]
- Cyclothymia
- Substance/medication-induced depressive disorder
- Depressive disorder due to another medical condition
Read More About Types Of Depression
Causes Of Depression
There are a variety of risk factors that have been associated with depression, such as –
- Genetics
- Hormonal dysfunction
- Negative experiences in childhood
- Certain lifestyle choices, etc.
Read More About The Causes Of Depression
Treatment For Depression
Depression, if untreated, can negatively impact your quality of life, everyday functioning, and interpersonal relationships. Hence, a timely and accurate diagnosis by a professional is quite important.
Despite the stigma and misconception surrounding it, depression is a treatable condition that can be easily managed in the long term with the help of therapy, medication, and healthy coping strategies.
Read More About How Depression Can Be Treated and Coping With Depression
Takeaway
Depression is a common but crippling mental disorder. If unchecked, it can seriously hamper our quality of life. Despite its longevity and low prognosis rate, it can be easily managed with therapy and medication. However, the first step towards treating depression is acknowledging its symptoms and the need for medical help.
At A glance
- Depression is a mental health disorder in which a person experiences low moods and an aversion to activity.
- It affects approximately 350 million people worldwide.
- If untreated, depression can result in poor personal and professional lives as well as suicide in extreme cases.
- It can range from mild, temporary episodes of sadness to severe, persistent depression.
- It is caused by several factors, namely, genetics, stress, trauma, interpersonal conflict, etc.
- It can be easily addressed with therapy, medication, and self-help strategies.
Frequently Asked Questions (FAQs)
1. What is the difference between depression and major depressive disorder?
A regular depressive episode can last for about two to three weeks. Major depressive disorder is a type of depression that consists of multiple depressive episodes and lasts for at least 2 months.
2. Is depression more common in women?
Yes 11. More women than men are diagnosed with depression.
3. Does depression cause sleepiness?
Yes. People suffering from depression are prone to disrupted sleeping patterns. This can involve hypersomnia, or excessive sleepiness.
4. Can depression cause a heart attack?
For people with heart disease, depression increases the risk of an adverse cardiac event 12 such as a heart attack or blood clots.
5. What is the difference between clinical depression and subclinical depression?
Clinical depression is diagnosed if 5 or more major symptoms of depression are present in a person, as laid down by the DSM 5. On the other hand, subclinical or subthreshold depression involves symptoms that do not meet the full criteria for a depression diagnosis.
Take This Free Depression Test

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- World Health Organisation. (2021, September 13). Depression. World Health Organization; World Health Organization. Available from: https://www.who.int/news-room/fact-sheets/detail/depression [↩]
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- Rohan, K. J., Rough, J. N., Evans, M., Ho, S. Y., Meyerhoff, J., Roberts, L. M., & Vacek, P. M. (2016). A protocol for the Hamilton Rating Scale for Depression: Item scoring rules, Rater training, and outcome accuracy with data on its application in a clinical trial. Journal of affective disorders, 200, 111–118. https://doi.org/10.1016/j.jad.2016.01.051 [↩]
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- Heart disease and depression: A two-way relationship | National Heart, Lung, and Blood Institute (NHLBI). (2017, April 16). Nih.gov. Available from: https://www.nhlbi.nih.gov/news/2017/heart-disease-and-depression-two-way-relationship [↩]