Where this comes from
A behaviour is reinforced because it gives pleasure, but also because it removes discomfort. The second process — I feel bad, I do something, I feel better for a while — is what keeps addiction running long after the pleasure has gone.
The mechanism is well known. What we do not measure well is its dynamics over time: how fast need rises, how quickly it subsides, and how much of it never subsides at all.
The question, in one line
In people with addiction, is the dynamics of need and its recovery measurable in a repeatable way, and does it distinguish those who relapse from those who hold?
This is not the question of who becomes addicted and who does not. Answering that requires observing people before they lose control. We say so at the outset because it is the most important limitation of this first phase — and because the project includes a phase two aimed at exactly that question, conditional on the first phase passing its gates.
Why measure rather than ask
The models that best predict relapse today rest on what a person reports several times a day. It is a strong signal, but an expensive one to collect: it asks someone to record how they are doing every day, precisely on the days they are doing worst.
An instrumental measure neither replaces that account nor discredits it. It observes something else. If the two diverge, that disagreement is itself worth studying, not an error to be corrected.
What "measuring" means here
Take the word in its strict sense. Just as an ultrasound machine does not measure a diagnosis but a return time and an echo amplitude, three levels are distinguished here, and must not be conflated:
- The recorded signal: a voltage difference, an interval between beats, a concentration.
- The estimated function: how slowly the system returns to where it started. It has a unit and an uncertainty.
- The attributed meaning: that this function contributes to vulnerability. This is the result to be demonstrated, not the starting point.
Much of the work consists in not jumping from the first to the third.
What it does not promise
This is not a diagnostic instrument. It does not tell a person whether they are addicted, and it does not predict their next relapse. An abnormal value on a laboratory task does not describe who you are.
The expected outcome, if the project works, is more modest and more useful: a repeatable instrumental test that shows whether a treatment is genuinely changing the dynamics of need.