Depression usually causes a variety of symptoms, such as: Intense sadness Hopelessness Empty feelings Helplessness Self-loathing Fatigue Loss of interest in hobbies or pursuits you once enjoyed Withdrawal from personal and social relationships Insomnia or sleeping too much Loss of appetite or greatly increased appetite Weight loss or gain Frequent thoughts about death Suicidal ideations With the most common form of depression, major depressive disorder, you experience severe symptoms lasting for at least two weeks. These symptoms are also common in other forms of depression such as postpartum depression after childbirth and persistent depressive disorder, which causes less severe depression symptoms but lasts for at least two years. Bipolar disorder features depressive episodes, in which you experience symptoms of depression. But, it’s a different disorder that requires its own approach to evaluation, diagnosis, and treatment.