About this time of year, farmers begin to sleep a little better. No risk of frost! But there are many reasons why people lose sleep. Analysis of insomnia by Doctors Vallières, Ivers, Beaulieu-Bonneau and Morin in their “Predictability of sleep in patients with insomnia” (Sleep. 2011 May 1;34(5):609-17) indicates that a 3-cluster predictability exists for the disease, indicating at least 3 classes of insomnia.
The Doctors explain “daily sleep diaries were completed for an average of 48 days and self-reported questionnaires once. Three nights were spent in the sleep laboratory for polysomnographic (PSG) assessment. Sleep efficiency, sleep onset latency, wake after sleep onset, and total sleep time were derived from sleep diaries and PSG. Time-series diary data were used to compute conditional probabilities of having an insomnia night after 1, 2, or 3 consecutive insomnia night(s). Conditional probabilities were submitted to a k-means cluster analysis. A 3-cluster solution was retained. One cluster included 38 participants exhibiting an unpredictable insomnia pattern. Another included 30 participants with a low and decreasing probability to have an insomnia night. The last cluster included 49 participants exhibiting a high probability to have insomnia every night. Clusters differed on age, insomnia severity, and mental fatigue, and on subjective sleep variables, but not on PSG sleep variables,” and conclude that “these findings replicate our previous study and provide additional evidence that unpredictability is a less prevalent feature of insomnia than suggested previously in the literature. The presence of the 3 clusters is discussed in term of sleep perception and sleep homeostasis dysregulation.”
The National Sleep Foundation's 2002 Sleep in America poll showed that 58% of adults in the U.S. experienced symptoms of insomnia a few nights a week or more. The causes of insomnia are numerous, ranging from second hand marijuana to physical defects of the brain, but this study presents a new take on this common illness by reducing the number of ways that the body reacts to insomnia – either with more insomnia or less insomnia.