Soal Pilihan GandaManic depression is another psychiatric illness that mainly affects the mood. A patient suffering from this disease will alternate between periods of manic excitement and extreme depression, with or without relatively normal periods in between. The changes in mood suffered by a manic-depressive patient go far beyond the day-to-day mood changes experienced by the general population. In the period of manic excitement, the mood elevation can become so intense that it can result in extended insomnia, extreme irritability, and heightened aggressiveness. In the period of depression, which may last for several weeks or months, a patient experiences feelings of general fatigue, uselessness, and hopelessness, and, in serious cases, may contemplate suicide.

9. The paragraph preceding this passage most probably discusses ......

(A) never undergo mood changes
(B) experience occasional shifts in mood
(C) switch wildly from highs to lows
(D) become highly depressed