Theory 20/Life, Medicine & Mind /Chronobiology
Cycling Follows Circadian Amplitude
Cycling is treated as a mood dynamic. It may be a property of the clock.
The period of bipolar cycling is set by the amplitude of the circadian oscillator rather than by mood regulation, so rhythm-stabilising interventions should lengthen cycle time and reduce episode frequency.
01The evidence
Sleep and rhythm disruption precede episodes, and chronotherapy lengthens time to recurrence in bipolar disorder.
02The tension
Models emphasise mood feedback and kindling. Those predict cycling from episode history and do not explain why rhythm interventions work.
03The mechanism
A weak circadian amplitude allows the sleep-wake cycle to drift, and drift triggers state changes. A strong amplitude holds the phase and lengthens the interval between switches.
That makes amplitude the determinant, and predicts that stabilising the clock should lengthen cycles.
04What this is not
Those models predict from episode history. This predicts from clock amplitude.
05Predictions
- P1Cycle length should track circadian amplitude.
- P2Amplitude strengthening should delay recurrence.
- P3Rhythm disruption should predict episodes.
06Refutation
Cycle length independent of amplitude would favour mood-dynamic models.
07What it changes
It would make chronotherapy first-line.