Mental illness and ultradian rhythms
In the relatively new 24 hour, always on the go, digital lifestyle we live — might living a structured life with regularly established mealtimes and early bedtimes lead to a better life and perhaps even prevent the onset of mental illness? Well according to a new study, it might do just that, you could have a better quality of life just by being a little more structured thanks to our circadian rhythm.
For those who don’t know, our daily sleep-wake cycle is governed by an internal 24-hour timer, the circadian clock. However, there is evidence that daily activity is also influenced by rhythms much shorter than 24 hours, which are known as ultradian rhythms and follow a four-hour cycle. Most prominently observed in infants before they are able to sleep through the night, ultradian rhythms may explain why, on average, we eat three meals a day that are relatively evenly spaced across our daily wake period.
These four-hour ultradian rhythms are activated by dopamine, a key chemical substance in the brain. When dopamine levels are out of kilter — as is suggested to be the case with people suffering from bipolar disease and schizophrenia — the four-hour rhythms can stretch as long as 48 hours.
With this study, conducted on genetically modified mice, researchers demonstrated that sleep abnormalities, which in the past have been associated with circadian rhythm disruption, result instead from an imbalance of an ultradian rhythm generator (oscillator) that is based on dopamine. The team’s findings also offer a very specific explanation for the two-day cycling between mania and depression observed in certain bipolar cases: it is a result of the dopamine oscillator running on a 48-hour cycle.
This work is groundbreaking not only because of its discovery of a novel dopamine-based rhythm generator, but also because of its links to psychopathology. This new data suggests that when the ultradian arousal oscillator goes awry, sleep becomes disturbed and mania will be induced in bipolar patients; oscillator imbalance may likely also be associated with schizophrenic episodes in schizophrenic subjects. The findings have potentially strong implications for the treatment of bipolar disease and other mental illnesses linked to dopamine dysregulation.
So what does this mean for people like me or you, well the short answer is the boring one — regular sleep and meals keep your hormones running smoothly. The longer and more complicated answer is of course that no matter what we do in life, we have control over certain risk factors that set the quality of life for ourselves in later years.
Blum, I., Zhu, L., Moquin, L., Kokoeva, M., Gratton, A., Giros, B., & Storch, K. (2014). A highly tunable dopaminergic oscillator generates ultradian rhythms of behavioral arousal eLife, 3 DOI: 10.7554/eLife.05105