I need not detail how the idea recurred a dozen times a day and brought the fear that she was going insane. She stopped nursing the baby at night, got a good rest, and the idea disappeared. She was "able to shake off" when rested that which was a hideous obsession when fatigued. Indeed, one might speak of persons of this type as hypothymic as well as cyclothymic.
The hypothymic are those whose stock of courage and hope is easily exhausted, who become easily discouraged. They are borrowers of energy and vigor, they need sturdier folk around them; often they are said to be sensitive, and while this is sometimes true, it is more often the case that they are more affected.
The extraordinary complexity of human character is well illustrated by C. D. She is hypothymic or cyclothymic to the little affairs of life and to the minor illnesses. Yet when her family fortunes were greatly imperilled by a financial crisis, she stood up against the strain far better than did her husband, a man sturdy and buoyant in most of the affairs of life.