Lewis was depressed for about six months. now, however, he feels so good, so energetic, and so confident of himself that he decides to take all his savings out of the bank and invest it in fish-tank equipment. he believes he has discovered a way to "make fish live forever," and he talks so rapidly and so excitedly to his neighbors about his idea that they can hardly understand him. lewis most likely suffers from

Bipolar disorder.

Explanation:

After being depressed for about six months, Lewis starts talking so rapidly and so excitedly to his neighbors about his new idea that they can hardly understand him. Lewis most likely suffers from bipolar disorder. Manic-depressive illness or bipolar disorder causes unusual and clear shifts in mood, energy levels, and activity levels. As happened with Lewis, after a depressed mood he shifts to excited mood and big energy and activity levels.

citizens were able to charge more for their goods and services