It was formerly known as manic-depressive illness. It’s a chronic condition that affects the brain causing highs and lows in mood, behavior, energy, and activity. The manic highs and depressive lows give the condition its name. According to "Bipolar Disorder Risk Factors." Healthline Bipolar disorder usually first occurs between the ages of 15 - 30 years, with an average age of onset at 25 years. Bipolar disorder affects both sexes equally, but there is a higher incidence of rapid cycling, mixed states, and cyclothymia in women. According to "Bipolar Disorder." Tests and Diagnosis. Bipolar disorder is a challenging psychiatric condition. Formerly called manic depression, this chronic and potentially debilitating disorder is known for causing severe swings in mood and energy levels. People who suffer from bipolar I disorder, which is the most severe form of the disorder, don’t have the normal ups and downs most people experience in life. Their ups are really up, consisting of elated, giddy, and super-energetic manic episodes lasting for a week or longer. Their downs are often really down, comprised of hopeless, helpless, and even