Critical instability
The unrest that precedes a transition — not a derailment, but a herald.
Critical instability refers to the strong fluctuations that occur just before a system passes from one order to another. They are, in the language of synergetics, the precursors of an order transition in self-organising processes.
When a system finds itself between two patterns — the old order losing its grip, the new not yet settled — an intermediate state arises marked by unrest and large fluctuations. Chance and unpredictability then play a great role. One distinguishes transitions in which order arises out of disorder from transitions between different forms of dynamic order; in both cases it is precisely these critical fluctuations that announce the transition.
Unrest as turning point, not relapse
For clinical practice this is an important and encouraging insight. An increase in fluctuations — a patient becoming more volatile, with mood and complaints swinging more sharply — need not be a sign of deterioration. It may, put cautiously, be a herald of an imminent reordering. Schiepek and colleagues have shown that such critical fluctuations are measurable in therapy courses and often precede a meaningful change.
This connects to the early warning signals discussed elsewhere in this lexicon. It asks of the clinician a certain tolerance for unrest: not every increase in instability needs to be damped at once. Sometimes enduring a phase in which the outcome is not yet fixed is precisely the condition under which the new can present itself.