Circadian Rhythms and Mood Disorders (e.g. Depression, Bipolar Disorder)

Last month I answered some questions for a journalist writing an article on circadian rhythms and mood disorders (including depression and bipolar disorder). The article isn’t out yet but I wanted to give some practical information and tips because its an important topic.

Circadian Rhythms are our 24 hour clock. They’re how we stay synchronized with the world around us. Being in good rhythms helps us feel good. Being dysregulated is unsettling and can feel out of control.

Circadian rhythms are kept in sync by “zeitgebers” a word that means “time givers.”

For example, one zeitgeber is light/dark which causes us to generally want to sleep at night and wake up in the day.

Sleep times, mealtimes, exercise, and social stimulation, are all zeitgebers that help us keep in good rhythms/harmony.

Each of us has multiple circadian clocks. These include a master clock in a part of the brain called the suprachiasmatic nucleus (SCN). Our circadian clocks can become out of sync with the external world or can become out of sync with each other.

Different clocks are sensitive to different zeitgebers. For example, the circadian clock in the liver is particularity sensitive to mealtimes. Clocks in the muscles are sensitive to exercise.

The Links between Life Stress or Change, Circadian Rhythm Regulation Problems, and Mood Disorders

When life stress or other factors disrupt our zeitgebers our rhythms can become disrupted.

People differ in a) how easily their circadian rhythms get disrupted, and b) how easily their system can get itself back to equilibrium. A vulnerability factor for developing a mood disorder is if your rhythms are easily disrupted and your system has a harder time getting itself back to equilibrium.

What also happens is a cycle in which

1. people’s biological rhythms get disrupted
2. the disruption in their rhythms disrupts their life and behaviour, which
3. further disrupts their rhythms and makes it harder to get back to equilibrium.

Some of the clues that circadian rhythms are disrupted in people with mood disorders are:

– Lack of sleep can trigger mania or hypomania in people with bipolar disorder. Interestingly, intentional sleep deprivation can also lead to short term mood improvement in people with depression.

– A common symptom of depression is “early morning awakening” i.e. waking up several hours earlier than usual and not being able to get back to sleep. A person who has early morning awakening when they are depressed often also has less appetite than usual when they are depressed.

– A smaller group of people with depression have the opposite pattern of wanting to sleep a lot and feeling more hungry than usual.

– People who have mood disorders tend to have more sleep difficulties outside of their mood disorder episodes compared to people who have never been depressed.

– Sleep symptoms are often one of the last symptoms to “come right” when someone is recovering from depression.

– One type of depression is Seasonal Affective Disorder (SAD), in which people have difficulty adjusting to the onset of winter. (There is also a spring/summer version of SAD but its far less common than the winter version).

– Lots more.

What You Can Do.

If you think you’re someone whose rhythms get out of sync then you should consider keeping your zeitgebers on a consistent schedule. That is, keeping your sleep/wake times, mealtimes, exercise times/intensity, and social stimulation, consistent.

You may need more regular cues/more time for winding down and winding up than other people (e.g. a consistent bedtime routine that perhaps starts a couple of hours before bedtime. And likewise, a consistent waking up routine). You might think about what types of social stimulation work best for you (do some types of social stimulation feel overstimulating?)

Its probably particularly important that you keep your zeitgebers consistent during times of life stress or change.

Further information for other psychology PhDs or counsellors

For other psychology PhDs or counsellors who are reading this: a good, practical paper on this subject that has relevance to depression treatment and bipolar disorder treatment is:

Sleep and Circadian Rhythms in Bipolar Disorder: Seeking Synchrony, Harmony, and Regulation. Allison G. Harvey. Am J Psychiatry 2008; 165:820-829