Cyclical behavior is a pattern in which a person acts in seemingly opposite ways at different times. Often one way builds tension and the other releases it, (but not in a satisfying way.) Each extreme sets up and makes possible the other extreme. The cause is internal conflict (or 'splits') which are acted out in rotation, rather than reconciled. Common examples are addictive behavior with abstinence, promiscuous behavior with prudishness, dieting with binging, closeness versus distance in a relationship etc.
Cyclical behavior produces quite a bit of drama. The common stem of the contradictory behavior is not understood. Other people tend to shift their behavior in response to the seeming change, which tends to deepen the swings. There is often repetition of elation and disheartening.
What doesn't happen is neither the cycler, or the frequently present enabler, takes a sustainable stance that addresses the underlying unmet need in a healthy way. Rather all parties stay in crisis mode, and lose self-focus and purpose. Often immense energy is wasted trying to control the situation, which is falsely reinforced when the inevitable swing in the other direction seems to indicate that the controlling tactic 'is working.' In this circumstance, it is difficult to learn from experience, because approaches that will never really work seem to 'start to work.' The problem comes to be seen as complicated and elusive, when in fact, it is simple but requires hard choices to surmount.