Acute and Chronic Insomnia: What Has Time and/or Hyperarousal Got to Do with It?

Ivan Vargas,Célyne H Bastien,Michael L Perlis,Anna M Nguyen,Jason G Ellis,Alexandria Muench

doi:10.3390/brainsci10020071

Abstract

Nearly one-third of the population reports new onset or acute insomnia in a given year. Similarly, it is estimated that approximately 10% of the population endorses sleep initiation and maintenance problems consistent with diagnostic criteria for chronic insomnia. For decades, acute and chronic insomnia have been considered variations of the same condition or disorder, only really differentiated in terms of chronicity of symptoms (days/weeks versus months). Whether or not acute and chronic insomnia are part of the same phenomena is an important question, one that has yet to be empirically evaluated. The goal of the present theoretical review was to summarize the definitions of acute and chronic insomnia and discuss the role that hyperarousal may have in explaining how the pathophysiology of acute and chronic insomnia is likely different (i.e., what biopsychological factors precipitate and/or perpetuate acute insomnia, chronic insomnia, or both?).

Highlights

There are two general, but fundamental beliefs about insomnia that are critically evaluated in this article: (1) Acute insomnia is a briefer form of chronic insomnia, and (2) insomnia is characterized by a state of hyperarousal
It is argued that the distinction between acute and chronic insomnia needs to be the subject of empirical investigation, especially when evaluating the role of hyperarousal in the pathophysiology of insomnia
The ICD-11 does not specify quantitative criteria for insomnia frequency or chronicity and none of the diagnostic systems utilize a quantitative threshold for severity

Summary

Introduction

There are two general, but fundamental beliefs about insomnia that are critically evaluated in this article: (1) Acute insomnia is a briefer form of chronic insomnia, and (2) insomnia (regardless of its chronicity) is characterized by a state of hyperarousal. Brain Sci. 2020, 10, 71 has been variably defined as more than 1 month [11], 3 months [12], or 6 months [3], and AI has been variably defined as shorter than each of these duration thresholds Still yet another problem, one that extends to CI, is that AI has not been defined based on quantitative criteria for sleep continuity disturbance The ICD-11 does not specify quantitative criteria for insomnia frequency or chronicity and none of the diagnostic systems utilize a quantitative threshold for severity (i.e., adopt the 30-minute rule that is commonly used for clinical research [13,16]). Acute insomnia may occur in association with hypercortisolemia [23], while chronic insomnia may occur in association with hyperorexinemia [24] or abnormally low levels of γ-aminobutyric acid (GABA) [25]

Prevalence and Incidence of Acute and Chronic Insomnia

Defining “Hyperarousal”

Hyperarousal in the Context of Insomnia

Hyperarousal May Apply to Acute but not Chronic Insomnia

Findings

Where to from Here?