It's natural to feel down sometimes, but if that low mood lingers day after day, it could signal depression. Major depression is an episode of sadness or apathy along with other symptoms that lasts at least two consecutive weeks and is severe enough to interrupt daily activities. Depression is not a sign of weakness or a negative personality. It is a major public health problem and a treatable medical condition.
Depression causes feelings of sadness and/or a loss of interest in activities once enjoyed. It can lead to a variety of emotional and physical problems and can decrease a person’s ability to function at work and at home.
Depression can affect anyone—even a person who appears to live in relatively ideal circumstances.
Several factors can play a role in depression:
Biochemistry: Differences in certain chemicals in the brain may contribute to symptoms of depression.
Genetics: Depression can run in families. For example, if one identical twin has depression, the other has a 70 percent chance of having the illness sometime in life.
Personality: People with low self-esteem, who are easily overwhelmed by stress, or who are generally pessimistic appear to be more likely to experience depression.
Environmental factors: Continuous exposure to violence, neglect, abuse or poverty may make some people more vulnerable to depression.
Symptoms of depression can include:
Reduced interest or pleasure in activities previously enjoyed, loss of sexual desire.
Unintentional weight loss (without dieting) or low appetite.
Insomnia (difficulty sleeping) or hypersomnia (excessive sleeping).
Psychomotor agitation (for example, restlessness, pacing up and down), or psychomotor retardation (slowed movements and speech).
Fatigue or loss of energy.
Feelings of worthlessness or guilt.
Worsened ability to think, concentrate, or make decisions.
Recurrent thoughts of death or suicide, or attempt at suicide.