It depends the level. If the cyclothimia is extreme, it's one manifestation of the Neurosis. If it is lighter, it can be a part of the personality** of the person who has it. In all the cases, it is important to well determine this level. Otherwise we can combine a psychotherapy / psychoanalysis with medication. That gives excellent results.
Have a nice day
** If this behavior is a part of the personality of someone, this person must learn to live with it. It's a work to do on oneself.