The science behind the engine.
Brume applies the just-in-time adaptive intervention (JITAI) paradigm. Where classic apps count days and react after the fact, Brume flips the logic: measure continuously, estimate risk windows, intervene before the peak. Here's how — and what the science says, or doesn't yet.
Three families, never mixed.
Every number belongs to a family. We never conflate them — it's the project's rule of rigor.
From a publication, always cited with its comparator, sample size (n) and reference.
A design goal or promise, flagged with "~" or "target".
A fictional interface value — plausible, coherent, never presented as a result.
Relapse isn't a failure of willpower.
The urge to smoke isn't a continuous state: it's a series of brief episodes (~3 min), triggered by conditioned contexts — coffee, the end of a meal, the break, alcohol. Smoking is a ritualized behavior, structured by the clock of the day. That's exactly what makes it predictable.
attempts on average before quitting for good. Relapse is the statistical norm, not a fault — Chaiton et al., 2016.
Just-in-time interventions.
A JITAI delivers the right support, at the right moment, only when the person needs it and can receive it (Nahum-Shani et al., 2018). Four components, mapped onto Brume:
The Smart-T trial (RCT, n=454, JAMA Netw Open 2025): verified abstinence at 26 weeks of 16.4% vs 10% for a standard app. It's the only smartphone JITAI validated for efficacy — Brume's scientific archetype.
Measure → Predict → Intervene.
A closed loop running at the scale of the day. Every episode outcome — urge ridden out or relapse — refines your windows.
Measure
Micro check-ins (EMA) of 6 questions, ~20 s. The 6 validated variables of Smart-T's risk score.
Predict
A hybrid engine, chronobiology-first. Time predicts better than place: 87.9% F1 across 1,784 episodes.
Intervene
A nudge ~20 min before the estimated window. A brief 60-second intervention, before the peak — not during.
- Craving intensity
- Stress level
- Alcohol intake
- Smokers around you
- Motivation to stay abstinent
- Cigarettes within reach
The dominant signal is time, not place. Removing GPS barely degrades the model; removing temporal features collapses it (npj Digital Medicine, 2025).
The safety net: an independent SOS.
Since the engine will miss episodes (AUC 0.63), an SOS urge button is always available — bypassing prediction, with no window condition. It stays free for life. Prediction helps you anticipate; it's never a single point of failure.
Our limits, in the open.
Scientific honesty is a trust asset, not a weakness. Three limits, publicly owned.
Fine-grained prediction stays modest
Forecasting an episode an hour ahead with ML alone tops out at AUC ≈ 0.63 — barely better than chance. It's the field's structural limit.
An app isn't a treatment
Nicotine replacement and varenicline remain the reference treatments. Brume always points to a professional and a quitline.
The companion supports engagement
The avatar boosts content use (+30%), not abstinence directly. We'll never claim otherwise.
Every choice, a study.
Ready to see the craving coming?
Do the 60-second profile and join the first cohort. Free for the first sign-ups.
Brume is behavioral wellness support — not a medical device. Need help quitting? Reach out to a quitline.