CBT-I in your pocket. Nothing else.

What it is

Six weeks. A diary. An algorithm that titrates your sleep window based on how you actually slept. A few reminders. That is the whole app.

CBT-I outperforms sleeping pills long-term and is the recommended first-line treatment by the American Academy of Sleep Medicine, the European Sleep Research Society, and NICE. Until now there has been no mature, free, source-available implementation of it.

How it works

1. Week 1 — assessment

   Baseline diary, chronotype quiz (MEQ short form), sleep window setup.

2. Week 2 — sleep restriction

   The algorithm prescribes a tighter time-in-bed window from your baseline efficiency. Floor at five hours. Never lower.

3. Week 3 — stimulus control

   Bed for sleep only. Out of bed after 20 minutes of wakefulness. The diary tracks it.

4. Week 4 — cognitive

   Worry journal with a bedtime-window guardrail. Catastrophization reframes.

5. Week 5 — hygiene

   Caffeine log with a 5-hour half-life model and predicted milligrams at bedtime.

6. Week 6 — relapse prevention

   What to do when sleep degrades again. The protocol, written down.

The titration rule, in full

rolling sleep efficiency ≥ 85%  →  expand window +15 min
rolling sleep efficiency < 80%  →  contract window −15 min
otherwise                       →  hold
floor: 5 hours. non-adherent nights excluded.

No magic. No black box. The algorithm is in lib/domain/cbti/sleep_restriction.dart and is covered by fifteen unit tests.

What it does not do

• No sleep score. Efficiency is a number, not a verdict.
• No streaks, badges, or "perfect week" callouts. Orthosomnia is a documented harm — gamifying sleep makes insomnia worse.
• No cloud, no accounts, no telemetry. Data lives in SQLite on your device. Export to JSON or CSV when you want a copy.
• No wearable sleep-stage estimation. The accuracy isn't there yet.
• No supplements, nootropics, or pseudo-science. If it isn't in the CBT-I literature, it isn't in the app.
• No replacement for a clinician. Severe or persistent insomnia needs a sleep doctor.

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Evidence base

• Edinger JD & Carney CE. Overcoming Insomnia: A Cognitive-Behavioral Therapy Approach. Oxford, 2nd ed.
• Morin CM & Espie CA. Insomnia: A Clinical Guide to Assessment and Treatment. Springer.
• Qaseem A, et al. Management of Chronic Insomnia Disorder in Adults: A Clinical Practice Guideline. Ann Intern Med. 2016;165(2):125-133. (ACP first-line CBT-I recommendation.)
• Riemann D, et al. European guideline for the diagnosis and treatment of insomnia. J Sleep Res. 2017;26(6):675-700.
• Trauer JM, et al. Cognitive Behavioral Therapy for Chronic Insomnia: A Systematic Review and Meta-analysis. Ann Intern Med. 2015;163(3):191-204.
• Wilt TJ, et al. Pharmacologic Treatment of Insomnia Disorder. Ann Intern Med. 2016;165(2):103-112. (Hypnotic limitations.)
• Baron KG, et al. Orthosomnia: Are Some Patients Taking the Quantified Self Too Far? J Clin Sleep Med. 2017;13(2):351-354.

Not medical advice

noctos is a self-help tool that mirrors the structure of clinician-delivered CBT-I. It is not a medical device, does not diagnose disorders, and is not a substitute for evaluation by a sleep physician. If your insomnia is severe, has lasted more than three months, or is accompanied by mood symptoms, suicidal thoughts, snoring with breathing pauses, or excessive daytime sleepiness, see a clinician.