Circadian Rhythms and Bipolar Disorder: Scientific Update

It has been some time since I wrote a post on scientific research, which was to be the focus of this blog but I expanded it into many things bipolar while staying on the science side. This post is one way to indulge my hypergraphia.

In selecting articles to review for this blogpost, I first find articles I understand as many neuroscience articles can be highly technical. Second, I find articles that have some practical utility to people living with bipolar disorder. So I tend to avoid articles that are related to mice or other animals. 

The first article is about the circadian rhythms. According to the National Institute of General Medical Sciences (NIGMS), which is a part of the National Institutes of Health (NIH), circadian rhythms are the physical, mental and behavioural patterns that closely follow a 24 hour cycle. These patterns are found in most living things including animals, plants and even microbes. Chronobiology is the study of circadian rhythms. Produced by natural factors in the body, circadian rhythms are also affected by factors in the environment with light being the most important as it controls the genetic switches that influence these patterns. Circadian rhythms influence many bodily functions such as body temperature, hormone releases and sleep/wake patterns. 


Circadian rhythm characteristics in mood disorders: Comparison among bipolar I disorder, bipolar II disorder and recurrent major depressive disorder. Chung, JK, Lee, KY, Kim, SH et al. (012) Clinical Psychopharmacology and Neuroscience, Vol 10(2), Aug, 2012. pp. 110-116.

Summary of Findings
This Korea-based study used factor analysis to study data on how people experience the rhythms of day and night and found that people with mood disorders were more likely to be evening types than people with no mood disorders. Those with bipolar disorder I were more likely to have evening tiredness than those with bipolar disorder II. Those with bipolar I scored higher for morning alertness than people with recurrent major depressive disorder (RMDD).



The second article is highly technical and the practical implications are not as explicit but the findings are worth a mention because they reinforce the link between abnormal circadian rhythm patterns and bipolar disorder.

A survey of genetic studies supports association of circadian clock genes with bipolar disorder spectrum illnesses and lithium response. McCarthy, MJ, Nievergelt, CM, Kelsoe, JR, & Welsh, DK. (2012), PLoS ONE, 7(2) 

Summary of Findings
This study acknowledges the relationship between abnormal circadian rhythms and bipolar spectrum disorders and that this has inspired the search for genetic sources for this abnormality. However, to date there have been no significant findings from this research that would link genes to these abnormalities. The researchers list 3 factors that could be a reason for this lack of significant findings: 1. complex traits usually involve more than one gene; 2. circadian rhythms may be more complicated than they first appeared; and, 3. genetic risk for bipolar disorder could be spread among many illnesses. Without going into technical detail, the major finding was that their analysis revealed previously unrecognized links between bipolar disorder and circadian rhythms.

Circadian rhythms and bipolar disorder. Murray, G. (2010). Bipolar Disorders, 12(5), 459-472

Summary of Findings
This accessible article is a review of existing literature on the relationship between abnormal circadian rhythms and bipolar disorder. It does not present anything particularly new but does reinforce what is already known.

Sleep: the secret to even moods

According to the National Institutes of Health, chronic sleep loss or sleep disorders may impact up to 70 million Americans and cost up to $16billion in healthcare costs and $60billion in lost productivity. So sleep is a big deal, not only to people living with bipolar disorder, who often have sleep disorders related to the illness

but also to people in general.

GOOD SLEEP is as essential for health as is good nutrition and physical activity. Getting good sleep means going to bed when you are tired, falling asleep within 15-30 minutes, staying asleep for 6-8 hours, and waking up feeling rested.

Sleep has been the bane of my existence ever since I was a child and I have spent a lot of my life trying to sleep when my body has other ideas so I have spent a lot of time researching sleep and trying strategies that work and spent a chapter in my book, Bipolar 101, discussing sleep. Sleep behaviors are on the list of symptoms for both depressive and manic episodes. Lack of sleep triggers bipolar symptoms and makes existing symptoms worse so getting enough sleep is very important to the mental health of someone living with bipolar disorder.

For manic episodes sleep goes bye bye and the rush of being able to just go-go-go eventually puts us in the hospital if we don't get back on track. During a bout of depression many people would prefer not to get out of bed. Treatment for bipolar disord

er usually gets people back on track with their sleep but if sleeplessness continues then they are often treated with medications that induce sleep.

Sleep deprivation (sleep deficit) is also the leading cause of accidents (of all kinds) in the USA because the brain does not function well on lack of sleep. Too little sleep also weakens our immune system so that we are more susceptible to illness. So what I am saying in this post can apply to anyone, not just people living with mental illness.

The latest research suggests that a sleep routine that keeps our circadian rhythms (internal clock) on a regular schedule, also keeps the mind on an even keel.

How do we do this? By developing a sleep routine; and at a minimum your sleep routine should include the following:

1. Going to bed at the same time each night and getting up at the same time each morning. Everyday. No changes on weekends. This sets your internal time clock and helps keep your moods on an even keel.
2. Give yourself 30 - 60 minutes to prepare for bed and find a way of developing a habit in terms of the sequencing of your preparation. The point is to slow down the body so it is ready to go to bed. For example, you could start by taking your medications (in particular, medications that make you drowsy) so they have some time to take effect before getting into bed? Or if they are quick acting you may want to take them last. Make sure you have set your alarm or put a glass of water by the bed (this is especially for people suffering from the dry mouth side effects of many bipolar medications). Some people find a bath calming. Others find a shower either calming or stimulating so find the activities that work best for you.
3. A calming down activity such as meditation or yoga or reading (a calm book:). Drinking a cup of warm milk (which has naturally occurring ingredients that make people sleepy) or chamomile tea is also helpful.

Research has also shown that we sleep better in cool temperatures so make sure to turn off/down the heating in your room. A dark room also encourages sleep and if you cannot create a really dark room then sleep with a blindfold on. TVs should be banned from the bedroom. So should laptop computers and your cellphone, if you are having a hard time with distractions.

One of the best ways to get better sleep is to be physically active on a regular basis. For those who have trouble sleeping it is better if you exercise in the morning, because the body takes some time to calm down when you exercise so if you do it too close to your bedtime, your body may be to revved up to fall asleep.

If you want to know more about sleep and mental well-being and find evidence-based strategies for improving sleep, then check out a new publication by the Mental Health Foundation in the UK, which has published a free downloadable book on sleep called, 'Sleep Matters: The Impact of Sleep on Health and Well-Being', click here.

The National Institutes of Health also publishes a sleep guide called, 'Your Guide to Healthy Sleep' is available free if you click here.