depression
Meaning of depression: Not simply sadness turned up: the loss of interest and the physical changes are as central as the low mood itself.
Definition of depression
Depression is a mental health condition in which low mood, or loss of interest and pleasure in almost everything, persists for weeks or longer and interferes with daily functioning. It is accompanied by physical and mental changes including disturbed sleep and appetite, low energy, poor concentration, feelings of worthlessness and, in some cases, thoughts of death or suicide.
How does it differ from sadness or grief?
| Grief or ordinary sadness | Depression | |
|---|---|---|
| Course | Comes in waves, eases between them | Persistent, present most of the day nearly every day |
| Self-view | Usually preserved | Often marked by worthlessness or guilt |
| Pleasure | Still possible in other things | Widely blunted or absent |
| Function | Largely maintained | Work, relationships and self-care are affected |
Grief and depression can occur together, and a bereavement can precipitate depression, so the two are not mutually exclusive. The distinction rests on persistence, pervasiveness and the degree of interference with activities of daily living rather than on whether there is a reason for feeling low.
What forms does it take?
Major depressive disorder describes episodes reaching a defined threshold of severity and duration. Persistent depressive disorder describes a lower-grade but long-running low mood. Some episodes follow a seasonal pattern; others begin during pregnancy or after childbirth. An important distinction is depression occurring within bipolar disorder, where episodes of low mood alternate with periods of elevated or irritable mood and increased energy. It can look identical to depression on its own during the low phase, which is why a history of elevated periods is asked about. Depression can also be produced or worsened by physical conditions such as an underactive thyroid, by some medicines, and by alcohol or other substances.
Why does it accompany physical illness so often?
Serious illness brings pain, disability, disrupted sleep, uncertainty and loss of role, each of which contributes. Some conditions act more directly, through inflammation or through effects on the brain itself, and treatment can contribute too. Depression is common among people receiving treatment for cancer and other serious diseases, and it is easily attributed to the circumstances and left unaddressed, since fatigue, poor appetite and disturbed sleep belong to both the illness and the depression. Support from a mental health counselor forms part of care in many such settings.
Used in a sentence
The patient was screened for depression given several weeks of low mood and loss of interest in usual activities.
Good to know
Depression is distinguished from grief or situational sadness by its persistence, pervasiveness and interference with functioning rather than by low mood alone, and depression occurring as part of bipolar disorder is a separate condition that can look identical during a low phase.