The symptoms of depression — technically referred to as major depressive disorder — are characterized by an overwhelming feeling of sadness, isolation, and despair that lasts two weeks or longer at a time. Depression isn’t just an occasional feeling of being sad or lonely, like most people experience from time to time. Instead, a person who has depression feels like they’ve sunk into a deep, dark hole with no way out — and no hope for things ever changing (American Psychiatric Association, 2013).
A person who suffers from a major depressive disorder (sometimes also referred to as clinical depression or simply depression) must either have a depressed mood or a loss of interest or pleasure in daily activities consistently for at least a 2 week period. This depressed mood must represent a significant change from the person’s normal everyday mood.
Social, occupational, educational, or other important functioning must also be negatively impacted by the change in mood. For instance, when a person who’s depressed starts missing work or school, or has stopped going to classes or their usual social engagements (such as hanging out with friends).
Related: Types of Depression
Clinical depression is characterized by the presence of 5 or more of these depressive symptoms:
- Depressed mood most of the day, nearly every day, as indicated by either subjective report (e.g., feeling sad, blue, “down in the dumps,” or empty) or observations made by others (e.g., appears tearful or about to cry). (In children and adolescents, this may present as an irritable or cranky, rather than sad, mood.)
- Markedly diminished interest or pleasure in all, or almost all, activities every day, such as no interest in hobbies, sports, or other things the person used to enjoy doing
- Significant weight loss when not dieting or weight gain (e.g., a change of more than 5 percent of body weight in a month), or decrease or increase in appetite nearly every day
- Insomnia (inability to get to sleep or difficulty staying asleep) or hypersomnia (sleeping too much) nearly every day
- More days than not, problems with sitting still, including constant restlessness, pacing, or picking at one’s cloths (called psychomtotor agitation by professionals); or the opposite, a slowing of one’s movements, talking very quietly with slowed speech (called psychomotor retardation by professionals)
- Fatigue, tiredness, or loss of energy nearly every day — even the smallest tasks, like dressing or washing, seem difficult to do and take longer than usual
- Feelings of worthlessness or excessive or inappropriate guilt nearly every day (e.g., ruminating over minor past failings)
- Diminished ability to think or concentrate, or indecisiveness, nearly every day (e.g., appears easily distracted, complains of memory difficulties)
- Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideas without a specific plan, or a suicide attempt or a specific plan for committing suicide
A depressed mood caused by substances (such as drugs, alcohol, medications) is not considered a major depressive disorder, nor is one which is caused by a general medical condition. Major depressive disorder generally cannot be diagnosed if a person has a history of manic, hypomanic, or mixed episodes (e.g., a bipolar disorder) or if the depressed mood is better accounted for by schizoaffective disorder and is not superimposed on schizophrenia, a delusion or psychotic disorder.
Depression is also experienced as a loss of interest and energy in things the person normally enjoys doing, things like working, going out, or being with family and friends. Most people with this condition also experience problems with eating and sleeping — either too much or too little. A depressed person’s memory and ability to concentrate will often be impaired, too; they may also be more irritable or feel restless all the time.
Related: Teen Depression Symptoms
In keeping with updates to the major depressive disorder criteria in DSM-5 (the latest diagnostic manual used to diagnose mental disorders), a person can suffer from a major depressive episode during a period of bereavement or grief, such as after the loss of a loved one. This is a significant change from the previous diagnostic criteria, which did not give the diagnosis of major depression if the person was grieving over a significant loss in their lives. This change was made with the rationale that since bereavement may include great suffering for some people, it may induce an episode of major depressive disorder.
In other words, it’s not normal for the symptoms of bereavement to induce significant functional impairment, morbid preoccupation with worthlessness, suicidal thoughts, psychotic symptoms, or psychomotor retardation (a slowing of a person’s physical movements) for two months or more. Thus, when they do occur together, the depressive symptoms and functional impairment tend to be more severe and the prognosis is worse compared with bereavement that is not accompanied by major depressive disorder. Bereavement-related depression tends to occur in persons with other vulnerabilities to depressive disorders, and recovery may be facilitated by antidepressant treatment.
This criteria has been adapted for DSM-5.