December 03, 2021

Internal Rhythms, Sleep, and Suicide

In this recent summary From the Scientist, the researchers highlight how chronotype, or internal rhythms, raise the risk of sleep disturbance and associated suicidal thoughts in individuals more inclined to be night owls. Studies show that the restoration and reduced stress response that comes from sleep occurs during rapid eye moment (REM) conditions, which tend to concentrate towards the latter portion of the night. As a result, shortened sleep duration in those inclined to go to bed later may be a factor in mental distress. The difference between 7 and 8 hours of sleep isn’t merely 1/8 of a night’s sleep, it may dictate the presence or lack of REM, dreams, and a reset of one’s emotional keel. And as we’ve shared before, consistency in sleep habits is important to regulating all of the body’s clocks and rhythms.

Just as the world is set up for right-handed people and lefties experience some extra challenges, societal norms place us on schedules more aligned with larks. As the article highlights, this is particularly challenging during adolescent and teen years, when rhythms shift. Recent research suggests that these patterns may be influenced by gut bacteria. Perhaps it is worth considering a client’s or one’s own chronotype inclinations and making scheduling adjustments to get that hour of REM and address the effects of chronic sleep deficits. There is a movement for later school start times for this very reason.

Alternatively, if you are still inclined to explore ways to address this challenge, more information on circadian rhythms, light exposure, and some ways to potentially shift sleep timing can be found here. 


From the Scientist: 

Summary of “Insomnia symptoms mediate the association between eveningness and suicidal ideation, defeat, entrapment, and psychological distress in students”

By Daniel R.R. Bradford

What is Chronotype and Why Does it Matter?

Chronotype is the term that describes a person’s preferences for certain times of the day. People described as having an early chronotype prefer to wake relatively early in the day – even on days where their schedule isn’t dictated by work or school requirements – and tend to feel energetic in the morning and daytime. On the other end of the spectrum, people with a late chronotype usually prefer to wake later and are more productive in the afternoon and evening. Early and late chronotypes are sometimes described as larks and owls, respectively. Extreme variations can cause major disruptions to people’s sleep-wake patterns and are considered clinical disorders (e.g., delayed sleep-wake phase disorder), but most people exhibit only a slightly preference one way or the other.

Physiology is an important factor in this daily internal rhythm. The antique watch inherited as a family heirloom isn’t the only timepiece passed down through the family: chronotype is strongly affected by genetics. Our daily rhythms are rooted in a brain area called the suprachiasmatic nucleus. This internal timekeeper is closely related to our optic nerve and evolved to remain synchronised with the daily variation in light levels from the sun. There are also measurable differences in physiological manifestations of our chronotype, such as the time of day when hormones relating to wakefulness and sleepiness are expressed. Additionally, our preferences around sleep and wake timings vary naturally across the lifespan. On average, there is a two-hour shift towards lateness through adolescence and young adulthood. Notably, this is a time when symptoms of mental ill health first emerge in many people. This move toward lateness gradually shifts back earlier through adulthood.

However, individual behaviors and cultural factors play an important role in the day-to-day pulse of our lives too. With the widespread use of electric light, humans have been able to disconnect from the setting sun as a prompt that the day is coming to a close. The opportunity to engage in stimulating behaviors into the evening is both a blessing and a curse. On one hand it enables us to enjoy late-night socialising with friends and family that can be a great protective factor for positive mental health. Yet on the other, it lets us check work emails long after typical office hours, which can lead to a never-ending state of alertness and anxiety. Regardless of how we use this artificial extension of the day, people with a biological predisposition towards a late chronotype are more likely to feel energized and awakened by evening activities and must be more conscious of how these may impact their sleep-wake habits.  

Night Owls often Suffer

Having a late or early chronotype is not inherently good or bad, but a lot of research shows that owls typically have slightly poorer outcomes. Unfortunately, for people with a late chronotype, personal daily energy rhythms are often at odds with those typical in society. For many this may simply mean their friends, family, and colleagues know not to expect more than single-world responses before noon. And it goes unquestioned that so many people claim to require ingestion of a psychoactive stimulant before being able to function (a.k.a. their first cup of coffee). But for others with a late chronotype this misalignment of internal and external rhythms causes more serious problems: owls tend to get sleepy much later in the evening than their lark counterparts but must still wake up in time for the start of a typical workday or school schedule. This can lead to them getting consistently less sleep than necessary.

The majority of us will have experienced nights where, for whatever reason, we get less than the ideal amount of sleep. The next day we’re often unable to think clearly. We rage at the driver that cuts us off. The world seems gloomy. Everything just feels that bit harder to deal with. Even the most-saintly of us are more likely to snap at our dearest friends and family for the tiniest of infractions. In extreme cases, people have been found to experience more severe suicidal thoughts and behaviors following a night of insomnia. Usually, the poor night of sleep is a one-off, or due to some short-term stressor that passes in due course. With good quality and quantity of sleep restored we’re back to ourselves.

Unfortunately, people with late chronotypes are more likely to consistently get less sleep than is optimal. A growing body of research shows that being chronically under-slept has a wide range of negative consequences for health and well-being. It is important to recognize that these negative consequences can occur to a lesser extent even if we’re consistently sleeping only slightly less than our personal ideal. This type of sleep deprivation is more likely to occur over a longer period where the immediate next-day consequences may not be so obvious and noticeable compared to the after-effects of an acute episode of insomnia. People with a late chronotype are more susceptible to finding themselves in this situation of mild-yet-chronic sleep deprivation due to the misalignment between internal and external rhythms mentioned above. A personal account of the effect of having an extreme late chronotype on sleep and health throughout life can be found here.

Chronotype, Insomnia and Suicide

To explore how chronotype might be associated with suicidal thoughts and how these factors interact with sleep we carried out a survey of college-age adults. Our study measured the severity of the participants’ insomnia symptoms, where they were on the spectrum of late to early chronotype, and the severity of suicidal thoughts they had been experiencing (if any), as well as other domains of psychological distress. We initially found a mild association between a preference for evenings and an increased score on the measure of suicidal ideation severity (i.e., the more inclined towards being an owl someone was, the more likely they were to report experiencing more frequent or more intense suicidal thoughts). However, by accounting for the increased insomnia experienced by people with a late chronotype the direct link between chronotype and suicidal ideation was no longer statistically significant. What this indicates is that being inclined towards a late chronotype does not inherently predispose someone to experiencing poorer psychological well-being, but that this later rhythm may result in more severe symptoms of insomnia and consequences on a person’s mood and levels of distress. This increase in insomnia is most likely caused by the mismatch between a person’s chronotype and those rhythms imposed on them by the external environment, such as school and work schedules.

Our results suggest that more work should be done to explore the role of a person’s internal rhythms on experiences of suicidal thoughts and behaviors, as well as other aspects of psychological wellbeing. Other studies have shown that improving sleep quality through psychological medicine can improve mental health. These techniques often focus on behavior change such as improving sleep hygiene (e.g., keeping consistent daily wake times, avoiding stimulating activities such as exercise or media in the evenings). Yet these methods take discipline and, for some, are a sustained fight against a person’s physiology. They rarely account for or embrace the hard-wired biological factors that may mean an individual may consistently struggle to fit in with typical societal schedules. By appreciating that relatively well-fixed physiology can have a major impact on an individual’s sleep-wake behaviors, clinicians and these individuals may have a practical and simple tool to advocate for schedule shifts and support a subset of people at risk for mental distress and suicidal behaviors.

Note: The information provided on our site is for educational purposes only and does not constitute or substitute for professional medical advice. Please consult your healthcare provider before starting or stopping any treatment. We are not liable for risks or issues associated with using or acting on this information. If you or others need immediate attention please call the National Suicide Prevention Lifeline at 800-273-8255 or text the Crisis Text Line at 741741.