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An Overview of Depression

If you fail an important examination, lose a loved one or a job, or get dumped in a relationship, it is normal to feel depressed. But if you remain depressed for more than two weeks, long after the event has passed, then you may have a common clinical disorder called depression. Clinical depression, also called major depressive disorder, is characterized by a sad or blue mood that affects nearly every aspect of your life every day – your family and social relationships, your work or school performance, even your desire to do simple things such as exercise or go out with friends.

Depression is much more than just a bad mood, though. Countless people in the throes of depression often feel worthless, lack any appetite, withdraw from friends and family, have difficulty sleeping, and can become agitated or lethargic. Most worrisome of all, people who are depressed can often run a high risk of suicide.

But depression, even though it often feels like it for a person who is depressed, is not the end of the world. It is one of the most well-understood and readily treated and treatable mental disorders. Learning more about this issue is an important and courageous first step toward ending feelings of sadness and depression.

What causes depression?

Like most mental disorders, the causes of depression are largely unknown. Researchers and clinicians theorize that depression is the result of three related factors – biological, psychological and social. No doctor can tell you how much of any single factor is contributing to the diagnosis of depression within an individual. For some people, the biological factors, such as genetics, may be stronger than the other two. For others, it may be caused mainly by a psychological issue, such as one’s personality or way of coping with stress.

Theories about biological causes include ideas such as there is a chemical imbalance in the brain, or that some people carry a genetic predisposition to depression based upon certain genes inherited from one’s parents. Theories about psychological causes include ideas such as there is an internal dialogue that reinforces our negative beliefs about ourselves or our abilities, or that some people never learn adequate coping skills as they are growing up. Theories about social causes include ideas such as a person may have had difficulty establishing social skills in childhood, or have few or no friends or family connections as an adult.

What are some of the Risk Factors for Depression?

A risk factor is something that may increase your chances of getting depression or another condition. The risk factors for depression include:

  • Having previous episodes of depression or another mental disorder (such as anxiety, a sleep disorder, or a personality disorder)
  • Any life-altering or stressful event in your life (including both negative ones, such as the death of a loved one, or positive ones, such as the birth of a child or a wedding)
  • A family history of depression (or some other mental disorders within your family)
  • Being a woman or elderly
  • Chronic illnesss of any kind
  • Low self-esteem or having no or few friends
  • Feeling helpless or having little control over a situation in your life

Symptoms of Depression

A person who suffers from a major depressive disorder either have a depressed mood or a loss of interest or pleasure in daily activities consistently for at least a 2 week period. This mood change affects a person across all aspets of their life – social, work, school and such.
Clinical depression is characterized by the presence of the majority of these symptoms in a person, experienced nearly every day:

  • Depressed mood most of the day, as indicated by either the person’s own feeling (e.g., feeling sad or empty) or as observed by others (e.g., appears tearful). (In children and adolescents, this may be characterized as an irritable mood.)
  • Markedly diminished interest or pleasure in all, or almost all, activities most of the day
  • Significant weight loss when not dieting or weight gain (e.g., a change of more than 5% of body weight in a month), or decrease or increase in appetite
  • Can’t sleep (insomnia) or sleeping too much (hypersomnia)
  • Can’t sit still (psychomotor agitation) or have difficulty with physical movement (psychomotor retardation)
  • Fatigue or loss of energy
  • Feelings of worthlessness or excessive or inappropriate guilt
  • Diminished ability to think or concentrate, or indecisiveness
  • Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide

Certain medications or medical conditions can cause symptoms similar to depression, but depression is generally not diagnosed when the symptoms can be traced back to a specific medication or medical condition.

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An Overview of Depression

John M. Grohol, Psy.D.

Dr. John Grohol is the founder of Psych Central. He is an author, researcher, and expert in mental health online, and has been writing about online behavior, mental health and psychology issues since 1995. Dr. Grohol has a Master's degree and doctorate in clinical psychology from Nova Southeastern University. Dr. Grohol sits on the editorial board of the journal Computers in Human Behavior and is a founding board member of the Society for Participatory Medicine. You can learn more about Dr. John Grohol here.

APA Reference
Grohol, J. (2020). An Overview of Depression. Psych Central. Retrieved on September 25, 2020, from
Scientifically Reviewed
Last updated: 29 Jul 2020 (Originally: 17 May 2016)
Last reviewed: By a member of our scientific advisory board on 29 Jul 2020
Published on Psych All rights reserved.