Yes there is certainly a link between bipolar and depression. It is also known as manic depression. It is a depressive disorder and is severe because it is associated with the risk of getting thoughts of suicide, feeling of hopelessness and helplessness. Actually depressive disorders are of two types: bipolar disorder and major depressive disorder. The difference between major depression and bipolar depression is bipolar disorder is characterized by constant change in mood from severe highs to severe lows. The mood swing even in one day and the person feels all the symptoms of depression when he is suffering from bipolar disorder. Sometimes the person doesn’t even come to know about the symptoms of bipolar disorder for several weeks. Some of the symptoms of bipolar disorder are: 

1. Reduction in the sleep without feeling of fatigue.

2. Aggressive behavior with people and towards work.

3. Physical and mental activity of the person increases. The person is not able to make proper decisions and judgments.

4. Development of overconfidence, thousands of thoughts racing in the mind at the same time resulting in confusion.

5. The person suffering from this disorder is distracted easily and often gets frustrated and irritated.