Manic-Depressive (Bipolar) DisorderAlso known as 'Bipolar Disorder', this is a mental illness which consists of both depressive and manic episodes. During a depressive episode, the individual may feel pain, sorrow, unwillingness, anxiety, fear, pessimistic and unhappy. On the other hand, during a manic episode, the individual may feel extremely happy, courageous, energetic, grandiose, euphoric and may indulge in impulsive behaviors such as: spending absurd amounts of money or constantly changing jobs.