The exact changes in brain chemistry and function that cause either<unk> -life or earlier onset depression are unknown. It is known, however, that brain changes can be triggered by the stresses of certain<unk>  events such as illness, childbirth, death of a loved one,<unk>  transitions (such as retirement), interpersonal conflicts, or social isolation. Risk factors for depression in elderly persons include a history of depression, chronic medical illness, female sex, being single or divorced, brain disease, alcohol use disorder, use of certain medications, and stressful<unk>  events.
Late life depression
Depression 
Retarded depression
Double depression
Treatment-resistant depression
Outline of bipolar disorder
Depression in childhood and adolescence
Personality pathology