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Mental Health, Sleep, and Circadian Rhythms




Sleep: Most of us spend about a third of our lives in it, but many of us struggle to get in, out, and even define it. As the US National Institutes of Health put it, “Everyone needs sleep, but its biological purpose remains a mystery.” The details are vast and complicated, and we are only beginning to understand them. What we understand, however, has broad implications for all of us, and perhaps especially for those with mental health issues.

Why circadian rhythms fascinate me

Circadian rhythms are approximately 24-hour patterns of behavior and physiology, which are displayed by almost all cells of all life forms. They affect everything from mood to body temperature to blood pressure to growth hormone and yes, sleep. Circadian rhythms are created by molecular “clocks” that synchronize our internal time with what is happening around us.

Because our circadian system regulates almost everything in our body, its disruption has major consequences for our physical and mental health. The complex molecular and genetic world that comprises the circadian system remains a frontier of exploration in neuroscience. We’ve made great strides in learning how genes influence our biological clock, but how it affects sleep and how it affects and is affected by our mental health is much more complicated and difficult to untangle. The ability to investigate some of these mysteries is what drew me to this area of ​​research, particularly because the potential to help people is so great.

What is sleep?

Sleep is a behavioral state that is scientifically defined in terms of slower waves in brain activity. It is, however, a complex behavior involving multiple biochemical and neural circuits that work together in ways we don’t yet fully understand.

There are many catch-all terms that we often use casually in general conversation that actually refer to a scientifically complex set of things. Autism, for example, used to be used as a condition, whereas now we consider it a spectrum disorder. In recent decades, we talked about finding “a” cure for cancer, as if cancer were just a disease with a single cause, when we now know that it is unfortunately much more complicated. The idea of ​​sleep is somewhat similar. When you sleep, you’re not just turned off: part of your brain is inactive, but other parts are (in fact, should be) active.

What happens when we disrupt circadian rhythms

In modern society, our circadian rhythms can often be disrupted. Whether you’re working a factory line overnight or piloting a transatlantic flight with red eyes, nursing a baby or even just having a cup of coffee for breakfast, our bodies are often tricked into ignoring the information that tells him when to rest and when to be alert. Of course, many of these actions have benign effects.

But some people face a more extensive dysregulation of their circadian rhythms beyond their control, with sleep disturbances that create a mismatch between their sleep-wake pattern and the natural day/night cycle. An example is delayed sleep phase disorder, where people’s circadian rhythm is shifted later at night and later in the morning, causing them to not fall asleep and wake up at “normal” times. . Such profound disturbances can be extremely problematic: Studies have shown that the body’s inability to synchronize the sleep-wake cycle with its environment can lead to cognitive impairment, metabolic syndrome and mental illness. Even this knowledge is surprisingly new.

The Unmet Medical Need for Sleep Disruption

At present, circadian rhythm disruption and sleep disruption do not have good treatments. There are melatonin and melatonin agonists, but while melatonin is a great biomarker of change – it’s an output of our biological clock, and tracking it can help us track changes in our circadian rhythms – it is not very effective as a treatment for most people.

And there are sedatives and hypnotics, but these don’t provide all of the restorative effects of natural sleep. If we can genetically understand circadian rhythms, we can begin to understand the pathways they use and, therefore, the pathways that new treatments might take. And this, perhaps, will bring us closer to understanding the complex world of sleep.

Circadian rhythms and mental health: cause? Effect? Both?

Dysregulation of the circadian rhythm and the abnormal sleep that accompanies it were once thought to be just a side effect of mental illness. They often coexist, especially in conditions such as depression, bipolar disorder, and schizophrenia. It was often thought that perhaps a person’s mental health medications were causing poor sleep or that their distress was leading to disturbed sleep. Certainly, these things can happen.

Increasingly, however, we are investigating the converse: the extent to which circadian rhythm disruption might actually be the cause, not the result, of some cases of mental illness. And a third possibility also exists: mental health problems and sleep problems can, in some cases, both be caused by the same trigger. All three possibilities – or combinations of these possibilities – share the same hope: the better we learn to help improve sleep, the more we can help improve, or even eliminate, co-occurring mental health issues.

Keeping Circadian Rhythms Healthy

Our circadian rhythms are regulated by many things: by light, by time, even by temperature. You’ve probably heard tips for minimizing your screen time in the evening and taking advantage of natural sunlight during the day, especially early on, whether you’re crossing time zones or just hoping to be as alert as possible during your day. You’ve probably also heard advice on good sleep hygiene, keeping your bedroom dark, cool and quiet. It’s all true and backed by science! We may not have unraveled all the mysteries of sleep yet, but we’ve been able to uncover many evidence-based ways to help people keep their circadian rhythms as healthy as possible.

However, many people with neuropsychiatric disorders learn that their circadian rhythm abnormalities have deeper, sometimes genetic, causes. My work, and that of my colleagues, is in this vein. We study the mechanisms that link circadian rhythms and sleep to mental health problems and the genetics of circadian rhythms in sleep and mental health.

For example, we now know that there are circadian and clock-driven genetic mutations that play a role in the development of sleep, mental health, and metabolic disorders. We hope our work will help us understand how these complex processes work, how they work together, and how we can better understand them and develop effective treatments that can solve, or even prevent, these distressing problems.

Used with permission

Professor Aarti Jagannath

Source: Used with permission

Professor Aarti Jagannath is an Associate Professor at the Sleep and Circadian Neuroscience Institute at the University of Oxford, as well as Academic Co-Founder of Circadian Therapeutics. His group studies the basic neuroscience and molecular biology that underlies sleep and circadian rhythms, in particular the mechanisms that regulate circadian clock entrainment. In addition to being a research scientist, Professor Jagannath is an entrepreneur, educator and advocate for women in STEM. She is a fellow of the L’Oréal-UNESCO program for women in science as well as of the Research Council in Biotechnology and Biological Sciences.