The National Institute of Mental Health’s website states that there are three main types of depression: major depression, dysthymia andbipolar disorder. In the DSM, these are called major depressive disorder and dysthymic disorder, and bipolar disorder is considered a mood disorder. The website adds that general symptoms of depression include feeling sad, anxious or lacking feeling, having problems concentrating and remembering, feeling restless and irritable, having headaches and digestive issues, and losing interest in activities you enjoyed before. Suicidal thoughts or attempts can sometimes occur with depression.
The main differences between the various types of clinical depressioninvolve severity and time frame of symptoms and levels of functioning. In major depression or major depressive disorder, the DSM states that there can be a single episode or recurrent major depressive episodes.
https://www.empowher.com/mental-health/content/what-depression