Amy Senn, age 17, of Louisville, Ky., for her question:

WHAT CAUSES OUR MOODS TO CHANGE?

A mood is a person's state of mind or outlook on life.

Psychoanalysts have shown that a person's apparently unexplainable mood can be caused by unconscious thoughts, wishes or guilt feelings. If this is true, the doctors say, it is correct to think of mood disturbances as secondary causes of the symptoms of manic depressive patients. Manic¬depressive psychosis is a mental illness where the patient's mood is obviously disturbed. He may be sad or happy for no visible reason. His mood changes often. Some doctors have suggested that the basic trouble with such patients is a disturbance of mood.

Fortunately, most people have no problems with mixed up moods. There's a good balance with the ordinary routine of life and moods change only slightly as we meet and solve the problems of life and living. There are a few tears, but there are a lot more laughs.