Monday, May 17, 2010

The circadian prison

This post was chosen as an Editor's Selection for
I had no idea my sleep-wake cycle was pathological until I saw a presentation a few years ago by the geneticist Thomas Bourgeron. One of his interests is clock genes in autism. In fact only by speaking with him did it dawn on me that I lack a circadian rhythm.

As it turns out, autistics are considered to have circadian clocks "gone bad." Two reviews (Bourgeron, 2007; Glickman, 2010) cover the evidence with respect to autism and circadian rhythms, most of it in the direction of comprehensive atypicalities. Glickman (2010) summarizes the problem:
Disturbed sleep-wake patterns and abnormal hormone profiles in children with autism suggest an underlying impairment of the circadian timing system.
And autistic children's bad timing, when it comes to sleeping and waking, is considered disruptive or worse, both to themselves and their sleep-deprived families. Bourgeron (2007) raises the further concern that typical sleep-wake patterns are essential for "appropriate" development, for the functioning of memory, and so on. Apparently there is nothing good about autistics' bad circadian clocks.

Autistics whose sleep-wake cycles carry on independently from environmental and social cues are said to be "freerunning." My form of freerunning is extreme. I can sleep whenever I want--a few hours here, twelve hours there, as necessary, no matter the time of day or night. I enjoy sunlight but its absence has no effect on my mood, or on my sleep. I can work through nights, no problem, and shift to days in a blink. I've never suffered through jet lag. And so on. Until I ran into Bourgeron I had no idea this was considered pathological, at least in an autistic.

The usual response to freerunning in autism is to see this as an autism-related sleep disorder. There is very preliminary evidence that freerunning autistics can be successfully treated with melatonin. Bourgeron (2007) refers to a short case study about an autistic whose free-running was remediated by melatonin treatment.

Of course nonautistics take melatonin too. They put themselves through sleep hygiene routines and they go to sleep clinics in droves. They suffer terribly from shift work and jet lag, and inadequate efforts to eradicate this suffering are everywhere, from new drugs to new iPhone apps.

There is an enormous market for products and services that can treat individuals who stray from the proper expected sleep-wake cycle. Remarkably, the goal is never to free people from their circadian prisons but to return them there and keep them there. The schedule may be changed, with effort, but the prison remains the same.

The next time I spoke with Bourgeron, I told him there should be a sort of anti-melatonin which would allow people to freerun like me, ergo avoiding the ills of jet lag, shift work, and what-all. It seems possible no one has seriously thought of this.

I suggested the anti-melatonin idea to some nonautistic colleagues. They burst into stories about destroyed careers, disrupted lives. In constrast with autistics like me, my colleagues have perfectly "good" circadian clocks--which turn out to be incompatible with their challenging lives. They suffered, for being normally chained to their normal circadian rhythms.

If there was a pill that could give them my very dysfunctional clock so they could freerun to the extreme, they would buy it in bulk. But there isn't. Instead there is the assumption that everyone has to live in a circadian prison.

Glickman (2010) speculates that some autistics' failure to chain our sleep-wake cycles to environmental cues (you can find information about entrainment, as this process is called, here) may arise from our atypical perception. My totally wild guess might be that an extreme freerunning phenotype in autism may be contributed to in part by cognitive versatility in autism, which would result in perceived environmental cues affecting sleep-wake cycles in an optional rather than mandatory way.

The renowned Bora Zivkovic, who unlike me knows all about circadian clocks, recently wrote that--unlike me--typical people have "have complex circadian systems that are easy to get out of whack" with dire consequences:
In the state of almost permanent jet-lag that many of us live in, a lot of things go wrong. We get sleeping disorders, eating disorders, obesity, compromised immunity leading to cancer, problems with reproduction, increase in psychiatric problems, the Seasonal Affective Disorder, prevalence of stomach ulcers and breast cancer in night-shift nurses, etc.
BoraZ was writing enviously about reindeer who live with drastic changes of season yet have escaped this kind of misery, possibly by having a "low-amplitude" clock. They just stroll out of their circadian prisons, whenever it's adapative. How can poor suffering human beings do this, is the question--finally. It's a very good question.


Bourgeron, T. (2007). The Possible Interplay of Synaptic and Clock Genes in Autism Spectrum Disorders Cold Spring Harbor Symposia on Quantitative Biology, 72 (1), 645-654 DOI: 10.1101/sqb.2007.72.020

Glickman, G. (2010). Circadian rhythms and sleep in children with autism Neuroscience & Biobehavioral Reviews, 34 (5), 755-768 DOI: 10.1016/j.neubiorev.2009.11.017

Postscript: This post has been included in the 32nd edition of Scientia Pro Publica.