Abstract:Senile depression refers to depression that occurs after the age of 65, including the first depression occurring in old age and recurrent depression from earlier age of onset. Depression includes not only major depressive disorder, but also various types of depression. Many cases of senile depression are comorbid with organic diseases such as degenerative brain diseases and cerebrovascular impairment, and are affected by other factors including physical disease, environmental factors, and previous depressive episodes. Here, the heterogeneity of senile depression will be discussed to distinguish between different types of senile depression, suggest the corresponding diagnostic and therapeutic protocols, and provide references for clinical research, diagnosis, and treatment.