Feedback (coupling)
The mechanism that may drive addiction as well as recovery — and everything between.
Feedback — or coupling — belongs, in our view, to the most universal mechanisms in complex systems. It is what may turn a straight line into a spiral.
The basic idea is simple: the outcome of a process influences the process itself. If the outcome amplifies the process, we speak of positive feedback. A snowball that rolls and grows. A rumour that spreads. A panic attack that feeds itself. If the outcome dampens the process, we speak of negative feedback. The thermostat in the living room. Insulin production after a meal. The automatic correction on a bicycle leaning too far to the left.
Positive feedback is not positive
The terminology misleads. Positive feedback does not mean "good" — only "amplifying". A vicious cycle is positive feedback. Sleep problems lead to fatigue, fatigue leads to rumination, rumination leads to sleep problems. The system amplifies itself, and the downward spiral unfolds. The same mechanism also drives upward spirals: confidence leads to daring, daring to experiences, experiences to confidence. Both are positive feedback. The mechanism is identical; only the tone of the content differs.
"Vicious cycles and upward spirals work by exactly the same law. The question is only which way the system rolls."
Negative feedback keeps systems stable. It is why we do not simply remain feverish, do not forget to breathe, do not just fall off a chair. But negative feedback may also hold one captive — a system so "corrected" that it can no longer set itself in motion, no longer choose, no longer change.
Feedback in the consulting room
For mental health care, feedback carries meaning in three ways. Clinically: virtually all psychopathology may be understood as a feedback system. Depression as a negative spiral of inactivity and mood. Anxiety as positive feedback of avoidance and threat perception. Eating disorders as a coupling between body, control and emotion. One who thinks the system in terms of feedback sees at once which links sustain it.
Therapeutically: many interventions are attempts to break or reverse a feedback loop. Cognitive restructuring breaks the feedback between thought and feeling. Behavioural activation breaks the feedback between inactivity and mood. Exposure breaks the feedback between avoidance and anxiety. It is no coincidence that so many active elements of psychotherapy can be described as feedback interventions.
Methodologically: feedback makes psychological data inherently hard to interpret. For if A and B mutually amplify each other, what then is cause and what is effect? In a linear model this is an unsolvable problem. In a dynamical systems model — with time series, vector autoregression, or network analysis — it becomes answerable: we see over time which variable predicts which other.
What the thinking does
What strikes one repeatedly about feedback thinking is how natural it feels once one sees it. Patients recognise it immediately — they live it. The effort is for the clinician to consciously look for the feedback structures, and to design interventions that act on the loop, not only on the symptom. That is what process-based therapy attempts: from symptom suppression to the identification and reworking of the active feedback mechanisms.