Depression is a mood disorder characterized by persistently low mood and a feeling of sadness and loss of interest. It is not a passing problem, it lasts for 6-8 months on average.
Depression seems common amongst people, but is a serious mood disorder. It causes severe symptoms that affects how you feel, think, and handle your daily activities such as sleeping, eating, or working. To be diagnosed with depression, the symptoms must persist for at least two weeks. Some forms of depression are slightly different, or they may develop under unique circumstances. Some of the common symptoms include: Persistent sad mood, feelings of hopelessness, irritability, loss of interest in hobbies and activities, restlessness, difficulty in concentrating, remembering, or making decisions, difficulty in sleeping or oversleeping, loss of appetite, weight changes, suicidal thoughts, aches and pains, amongst others. These symptoms vary in people, not everyone experiences the same thing. It could be less for some and it could be more for others.
The causes of depression cannot be traced down to a single source, but it can be due to a complex combination of factors such as genetics, environmental, psychological and social factors, life events (divorce, childhood trauma, financial problems, relationships, medical concerns…) and drug abuse, amongst others.
Depression is a treatable mental illness that requires lots of patience. There are three major ways to help treat depression: The best way is support (from family members and friends especially), psychotherapy and drug treatment (anti-depressants). Beyond treatments, you could try to always stay active, set realistic goals and spend time with people who you confide in. Try not to isolate yourself and expect your mood to improve gradually, not immediately.
It would be helpful to do some research on depression so you can take a look at other ways it can be identified and dealt with.