Why are some individuals diagnosed with depression and not bipolar disorder?

Some individuals are dignosed with depression and not bipolar disorder because depression is more than just feeling low. It's a deep sadness or emptiness you can't shake. You might feel hopeless, worthless, and restless. You might lose interest in things that you used to enjoy. Depression often goes hand-in-hand with sleep problems, changes in appetite, and trouble concentrating. It can lead to suicidal thoughts or actions. People who suffer with depression might have some days that are better than others. But without proper treatment, their mood tends to remain low. Whereas bipolar disorder is different. If you have it, you have extreme mood swings. You experience periods of depression. But you also have periods of great highs. Bipolar refers to the opposite ends, or poles, of the emotional spectrum. You might be severely depressed for a period of hours, days, weeks, or even months before entering a manic period. The mania could range from several days to two months or longer. It's also possible to have a type of bipolar disorder in which you experience manic and depressive symptoms at the same time. You might feel sad and hopeless but also be very agitated and restless.