What is the difference between sadness, grief and depression?

Sadness is considered a normal, healthy emotional reaction to minor losses and disappointments. Sadness is very transient, lasting only several minutes, a few hours, or, at most, a few days. It is unpleasant but typically doesn’t interfere with your functioning. Normal, minor bouts of sadness don’t knock you off your feet.

Grief is a much more intense and sometimes devastating human experience. However, it is considered an inevitable and normal emotional reaction that people in every culture across the world experience after a major loss, such as the death of a loved one or a divorce. Grief tends to have a major disruptive effect on the lives of the grief stricken and can result in prolonged periods of sadness, loneliness, and mourning, which can last anywhere from a few months to several years. Normal grieving may last a very long time; broken hearts do not mend quickly.

Grief is extremely painful, but it is not mental illness.

Grief also differs from depression in two other ways. With
normal grief reactions, your feelings of self-esteem are generally unaffected. Despite great sadness, you continue to believe that you are a worthwhile individual. In clinical depression, feelings of worthlessness, inadequacy, and lack of self-confidence are common. Also, there are four symptoms of depression that are absent during times of grief: serious thoughts about suicide, severe sleep disturbances, marked agitation, and a complete loss of aliveness and vitality.

Although the daily experience of a person grieving may be filled with feelings of loss and sadness, there is also the ability to experience moments of happiness. The grieving person may enjoy a funny movie, experience happiness when visiting a loved one, appreciate a nice meal, or enjoy seeing a beautiful landscape. Even while grieving, despite a good deal of suffering, thankfully, there can be times of pleasure and aliveness. Often, this is not the case with depression. With severe depression, most often there is no ability to experience even brief moments of happiness. Life feels boring, dull, and robbed of all vitality and meaningfulness.