Chronotherapy — re-aligning the clock with the PRC

Circadian disease is a phase gap, so the treatment is to re-align the clock with a PRC-correct zeitgeber. A correct-phase pulse closes a delay (2.56 → 0 h); the same pulse at the wrong phase worsens it (5.44 → 11.2 h). Timing is the therapy; mis-timed light or melatonin is iatrogenic. No new constant; efficacy = 0; not medical advice.

Treatment follows directly from the control law. A phase-correct zeitgeber re-aligns a delayed clock, while the same stimulus at the wrong phase drives it further off — so chronotherapy is a timing discipline in which the wrong phase is harmful, not merely ineffective. Light, melatonin (antiphase PRC), wake therapy (transient, no re-alignment) and behavioural entrainment are four levers on one curve. The directions are verified, clinical windows cited; efficacy is zero, the mood response is owned by mind, and none of this is medical advice.

chronotherapy = re-aligning the clock with a PRC-correct zeitgeber; the WRONG phase worsens it (timing is the therapy) = a PRC-correct advancing pulse closes a phase delay as strength rises (2.56→1.12→0 h, saturating at full correction); the SAME pulse at the WRONG phase GROWS the delay (5.44→11.2 h) — mis-timed light/melatonin is iatrogenic, not inert; four levers off one control law: timed light (morning advances / evening delays), timed melatonin (PRC ~antiphase to light, reproduced — evening advances), wake therapy (transient homeostatic lift, no clock re-alignment, relapses), behavioural entrainment (wider Arnold tongue); NO new constant (the §3 PRC in reverse), direction + antiphase [V], clinical windows [L], efficacy [O]=0, NOT medical advice (mood response owned by mind) [V direction] / efficacy=0. this chapter

Treat the timing, not the symptom

If circadian disease is a phase gap, the treatment is to re-align the clock — and the control law for doing so is the phase-response curve of §3. Timing is the therapy. Take a phase-delayed clock (the clock runs too late, as in delayed sleep-wake phase disorder) and apply a PRC-correct advancing zeitgeber. The delay closes as the pulse strength rises — the residual delay falls 2.56 → 1.12 → 0 hours and saturates at full correction. The clock re-aligns.

The same pulse at the wrong phase is iatrogenic

The sign is the whole therapy. Deliver the same pulse at the wrong phase — the delay region of the PRC — and it makes things worse: the residual delay grows 5.44 → 6.88 → 11.2 hours. Mis-timed light or melatonin does not do nothing; it drives the clock further from alignment. This is why chronotherapy is a timing discipline and why getting the phase wrong is harmful, not merely ineffective.

Light, melatonin, wake therapy, behaviour

Four levers, all read off the same control law. Timed bright light: morning light advances, evening light delays. Timed melatonin: its PRC is roughly antiphase to light (~12 hours apart, reproduced here), so evening melatonin advances a delayed clock. Wake therapy (sleep deprivation): a rapid but transient homeostatic lift of the depressed operating point (the mind seam) that does not re-align the clock and relapses after recovery sleep unless paired with a phase-stabilising lever. Behavioural entrainment (timed meals, activity, dark discipline): a stronger zeitgeber widens the Arnold tongue (§3) and stabilises the phase the other levers set.

What this section is not

No new constant enters: the correction is the §3 PRC applied in reverse, the per-pulse gain is [O], and only the direction (correct phase advances, wrong phase delays) and the antiphase light/melatonin relation are asserted ([V]), with clinical timing windows cited [L]. Efficacy is firewalled to zero. This is the clock's control law, not a dose, not an outcome, and not medical advice; the mood response to the timing change is owned by the mind volume.