Although depression may not have a single cause, and it's not exactly known what causes it, it is a real chemical change in the body and is a true mental illness. There are some factors that are predictive of an individual coming down with depression, including:  The death of a loved one. Separation from a loved one. Financial loss. Dramatic life changes such as relocating to a different city, retirement, or changing jobs. Conflicts in personal life such as divorce, disputes. Burnout or too much work. Additional responsibilities such as the birth of a baby or having to take care of sick parents or relatives. Conflicts in professional life such as changing roles and responsibilities that are not in sync with the person’s interests and skills. Physical, sexual, or emotional abuse. Debilitating diseases and illnesses such as HIV/AIDS, Parkinson’s, heart diseases, or cancer. Changes in the brain. Sometimes depression happens for "no good reason." However, a certain amount of sadness or difficult feelings are normal when bad things happen. If things don't improve after around 6 months, that's when a bigger problem is assumed to be at hand. Depression affects 6–7% of the total adult population in the US alone. The majority (70%) of diagnosed cases are seen in women — however this may be in part because women may be more comfortable than men in seeking treatment for depression and/or because of the higher risk of suicide in men. Suicide (a behavior associated with depression) is relatively common, too, being a leading cause of death nearly as common as influenza and pneumonia. The person's feelings of self-worth and self-confidence take a beating day in and day out thanks to their negative thought patterns. They are constantly pursued by thoughts which tell them they are not good enough, not lovable, wanted, or competent enough to be liked by others. They have persistent feelings that their company is not something people long for. So, in their mind, it's better to avoid interacting or mingling with people no matter...

TL;DR in Vietnamese:
Nắm được nguyên nhân gây ra trầm cảm. Nhận ra sự phổ biến của bệnh trầm cảm. Hãy để ý các dấu hiệu bất an khiến người đó xa lánh mọi người. Nhận ra sự xuất hiện của những thói xấu. Liệu trước sự thay đổi trong hiệu quả làm việc. Để ý tới những thay đổi về cân nặng.