What is a depressive episode?

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Depression is something we hear a lot about, but many people don't fully understand what it looks or feels like. This is partially because mental health has long been a taboo topic—something people were expected to keep to themselves or pretend didn't exist. But major depressive disorder (MDD) is a medical problem and more common than many realize.  

In fact, approximately 20 percent of adults in the United States experience MDD at some point in their lives.1 The COVID-19 pandemic has also exacerbated many risk factors for depression and has led to an increase in the prevalence of depression symptoms. 

It's important to recognize if you or your loved ones may be suffering from a major depressive episode (MDE) and how to get help. 


How to recognize symptoms of major depressive disorder 

MDD is different than sadness over a difficult life situation. The death of a loved one, illness, divorce or the loss of a job are all struggles that can cause grief. MDD is a mood disorder in which people experience a persistent feeling of a depressed mood or loss of interest in activities that they once enjoyed, combined with other symptoms. MDD impacts a person's quality of life and how they function day to day. 

One of the biggest challenges of depression is that many people don't realize that they have a mental health disorder. People living with MDD might see their symptoms as individual problems rather than signs of an underlying medical condition. But issues such as weight gain, insomnia and other symptoms combined with a depressed mood could point to something more. Additional signs of MDD may include:2

  • Changes in appetite or weight 
  • Change in sleep patterns 
  • Change in psychomotor activity—such as slowing down of mental or physical activities 
  • Fatigue or loss of energy 
  • Feelings of worthlessness or guilt 
  • Difficulty thinking, concentrating or making decisions 
  • Recurrent thoughts of death or suicidal ideation, or suicide plans or attempts 


How do I know if I'm having a major depressive episode? 

If you're suffering from five or more of the symptoms listed above, including a depressed mood, for more than two weeks, that may indicate a major depressive episode.3 When you're experiencing an MDE, you may feel like no one understands what you're going through. But you're not alone. In fact, a 2020 study found that approximately 21 million adults in the United States—over eight percent of the population—had suffered from an episode in the past year.4


What are the risks of major depressive episodes? 

It's important to take depression seriously, as it can greatly affect the quality of a person’s daily life, as well as relationships with loved ones, friends and family. Beyond this, major depressive episodes also lead to significant social and functional impairment,6 increased mental health care utilization7 and are a major economic burden with a cost of $326 billion in the United States in 2018.8


How frequently can depressive episodes happen? 

Studies estimate about 50 percent of people will only experience a depressive episode once. However, others may have recurring episodes throughout their lives. Research is identifying the causes of increased risk for recurrence, and some possible indicators may include: 

  • Family history of mental health conditions 
  • Cognitive processes (how we comprehend our environment and interpret knowledge) 
  • Personality traits such as neuroticism (which is a tendency toward negative feelings) 
  • Poor social support 
  • Stressful life events 

A 2007 study concluded that genetic factors contribute to the risk for recurrent depressive episodes. Depression may result from imbalanced signaling pathways, including deficits in GABA signaling in the brain.  

Ongoing research, scientific advances and increased focus on mental health can help to advance innovation in depression and help to address the unmet needs of people living with mental health conditions.  

If you're concerned about signs of MDD or experiencing MDEs, it’s important to talk to your health care provider. If you are having suicidal thoughts, dial 911 or seek emergency care immediately. U.S. residents can also reach the National Suicide and Crisis Lifeline by dialing 988. 

Learn about Biogen’s work to advance innovation in depression


1. Hasin DS, Sarvet AL, Meyers JL, et al. Epidemiology of adult DSM-5 major depressive disorder and its specifiers in the United States. JAMA Psychiatry. 2018;75(4):336-346.

2. Nierenberg AA, Husain MM, Trivedi MH, et al. Residual symptoms after remission of major depressive disorder with citalopram and risk of relapse: a STAR*D report. Psychol Med. 2010;40(1):41-50.

3. Screening for Depression in Adults and Older Adults in Primary Care: An Updated Systematic Review. National Institute of Mental Health Website. URL Accessed March 2, 2023.

4. Major Depression. National Institute of Mental Health Website. URL Updated January 2022. Accessed March 2, 2023. 

5. Erkki Isometsä. Suicidal Behavior in Mood Disorders—Who, When, and Why? Can J Psychiatry. 2014 Mar; 59(3): 120–130.

6. Romera I, Perez V, Menchón JM, Delgado-Cohen H, Polavieja P, Gilaberte I. Social and occupational functioning impairment in patients in partial versus complete remission of a major depressive disorder episode. A six-month prospective epidemiological study. Eur Psychiatry 2010. Jan;25(1):58-65.

7. Arnaud A, Suthoff E, DeRienzo L, et al. Tavares RM, Zhang X, Ravindranath AJ. The increasing economic burden with additional steps of pharmacotherapy in major depressive disorder. Pharmacoeconomics. 2021;39(6):691-706.

8. Greenberg PE, Fournier AA, Sisitsky T, et al. The economic burden of adults with major depressive disorder in the United States (2010 and 2018). Pharmacoeconomics. 2021;39(6):653-665. 

9. Burcusa SL, Iacono WG. Risk for recurrence in depression. Clin Psychol Rev. 2007;27(8):959-985.

10. Navneet Bains, Sara Abdijadid. Major Depressive Disorder. StatPearls Publishing LLC. January 2022.

11. Ettman CK, Abdalla SM, Cohen GH, Sampson L, Vivier PM, Galea S. Prevalence of depression symptoms in US adults before and during the COVID-19 pandemic. JAMA Netw Open. 2020;3(9):e2019686. 

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