Chronic insomnia disorder is persistent difficulty initiating or maintaining sleep, or non-restorative sleep, together with significant daytime impairment, despite adequate opportunity to sleep. It is among the most prevalent disorders in medicine and among the least mechanistically understood. The best supported framework is hyperarousal: insomnia is not a deficiency of sleep drive but an excess of arousal that opposes it, and the excess is measurable across autonomic, neuroendocrine, neuroimmune, electrophysiological, and neuroimaging domains, at night AND during the day. That 24-hour character is the framework's strongest claim - a purely nocturnal sleep-generation failure would not predict daytime hyperarousal, and it is why patients so often describe fatigue without sleepiness, and why they perform poorly on objective sleepiness testing in the opposite direction to the hypersomnolence disorders. Recent work locates the vulnerability more specifically in circuits regulating emotion and arousal, rather than in the circadian or homeostatic sleep-regulating circuits, and a large genome-wide analysis is consistent with that: insomnia's genetic architecture correlates substantially with psychiatric traits and implicates striatal, hypothalamic, and claustrum neurons rather than the classical sleep-switch nuclei.
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name: Chronic Insomnia Disorder
creation_date: "2026-08-24T00:00:00Z"
category: Neurological Disorder
parents:
- Sleep Disorder
- Neurological Disease
disease_term:
preferred_term: insomnia
term:
id: MONDO:0013600
label: insomnia
description: >-
Chronic insomnia disorder is persistent difficulty initiating or maintaining
sleep, or non-restorative sleep, together with significant daytime impairment,
despite adequate opportunity to sleep. It is among the most prevalent
disorders in medicine and among the least mechanistically understood. The best
supported framework is hyperarousal: insomnia is not a deficiency of sleep
drive but an excess of arousal that opposes it, and the excess is measurable
across autonomic, neuroendocrine, neuroimmune, electrophysiological, and
neuroimaging domains, at night AND during the day. That 24-hour character is
the framework's strongest claim - a purely nocturnal sleep-generation failure
would not predict daytime hyperarousal, and it is why patients so often
describe fatigue without sleepiness, and why they perform poorly on objective
sleepiness testing in the opposite direction to the hypersomnolence disorders.
Recent work locates the vulnerability more specifically in circuits regulating
emotion and arousal, rather than in the circadian or homeostatic
sleep-regulating circuits, and a large genome-wide analysis is consistent with
that:
insomnia's genetic architecture correlates substantially with psychiatric
traits and implicates striatal, hypothalamic, and claustrum neurons rather
than the classical sleep-switch nuclei.
notes: >-
ONTOLOGY CAVEAT, RECORDED DELIBERATELY. The bound term MONDO:0013600 carries a
`MONDO:ambiguous` synonym qualifier upstream and cross-references both
HP:0100785 (the phenotype) and NCIT:C28286. It is therefore the same class of
term as the one flagged for Rickets in the curation guidance: a single label
standing for both the symptom and the disorder. It is nonetheless the only
MONDO term for the concept, and chronic insomnia disorder is a distinct
clinical entity with its own diagnostic criteria and first-line treatment, so
the entry is curated with the term bound and the ambiguity noted rather than
omitted. Curators should not treat every KB use of HP:0100785 as an implicit
reference to this entry.
WHAT DOES NOT CONFORM, AND WHY IT MATTERS CLINICALLY. This entry deliberately
does not conform to circadian_phase_misalignment. The discriminator is
practical, not theoretical: in a circadian disorder, sleep is structurally
normal when the patient is allowed to sleep at their own phase, whereas here
sleep is disturbed at any phase. Delayed sleep-wake phase disorder is
routinely misdiagnosed as sleep-onset insomnia, and the two have opposite
treatments - timed light and melatonin versus cognitive-behavioural therapy -
so the boundary is worth the discipline. Nor does the entry conform to
orexin_arousal_instability, despite orexin's obvious relevance: dual orexin
receptor antagonists are an effective insomnia treatment, but pharmacological
responsiveness of a pathway is not evidence that the pathway is deranged, and
no orexin-system abnormality has been shown in these patients. That treatment
is curated as acting on the arousal node, not as evidence of an orexin lesion.
THE HYPERAROUSAL MODEL IS A FRAMEWORK, NOT A MECHANISM. It organises a large
and consistent body of measurement, but it does not specify a lesion, and the
entry curates it accordingly - as the central effector with an explicit
vulnerability arm above it, rather than as a trigger.
pathophysiology:
- name: Predisposing Vulnerability in Emotion and Arousal Circuits
description: >-
The trigger arm, and the level at which the disorder's causes actually sit.
Insomnia is substantially heritable, and the largest genome-wide analysis -
over 1.3 million individuals, 202 loci - shows enrichment not in circadian or
homeostatic sleep machinery but in cortical and subcortical tissues and in
striatal, hypothalamic, and claustrum neurons, with considerable genetic
correlation with psychiatric traits. Early-life stress, major life events,
and brain structural and functional variation contribute alongside. The
integrated reading is that vulnerability lies in circuits regulating emotion
and arousal rather than in circuits regulating sleep itself - which
reframes insomnia as a disorder of arousal regulation that manifests during
sleep, rather than as a disorder of sleep.
role: trigger
biological_scale: ORGANISM
evidence:
- reference: PMID:30804565
reference_title: "Genome-wide analysis of insomnia in 1,331,010 individuals identifies new risk loci and functional pathways."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We show gene set enrichments for the axonal part of neurons, cortical and
subcortical tissues, and specific cell types, including striatal,
hypothalamic, and claustrum neurons.
explanation: >-
Identifies the implicated cell types, which are notably not the classical
sleep-switch nuclei - the observation that motivates locating vulnerability
in arousal and emotion circuits.
- reference: PMID:30804565
reference_title: "Genome-wide analysis of insomnia in 1,331,010 individuals identifies new risk loci and functional pathways."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We found considerable genetic correlations with psychiatric traits and
sleep duration, and modest correlations with other sleep-related traits.
explanation: >-
The asymmetry is the point: insomnia's genetic architecture resembles
psychiatric traits more than it resembles other sleep traits, which is
direct support for the vulnerability being in emotion-arousal circuits.
- reference: PMID:32790576
reference_title: "Brain mechanisms of insomnia: new perspectives on causes and consequences."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
the integrated findings suggest that the vulnerability to develop insomnia
could rather be found in brain circuits regulating emotion and arousal than
in circuits involved in circadian and homeostatic sleep regulation
explanation: >-
States the localisation claim this node encodes, and explicitly excludes
the circadian and homeostatic circuits - which is also the basis for this
entry's non-conformance to the circadian module.
- reference: PMID:30804565
reference_title: "Genome-wide analysis of insomnia in 1,331,010 individuals identifies new risk loci and functional pathways."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The meta-analysis explained 2.6% of the variance.
explanation: >-
Cited as PARTIAL to bound the genetic arm: 202 loci in 1.3 million people
explain 2.6% of variance, so the genetics identify implicated circuits
without accounting for individual risk.
downstream:
- target: Persistent 24-Hour Physiological Hyperarousal
description: >-
Sensitised emotion-arousal circuitry, interacting with stressors, produces
a sustained elevation of arousal that is present day and night.
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Persistent 24-Hour Physiological Hyperarousal
description: >-
The central effector and the disorder's best-established abnormality.
Elevated arousal is demonstrable across independent measurement domains -
autonomic, neuroendocrine, neuroimmunological, electrophysiological, and
neuroimaging - and the convergence across modalities is what makes it robust
rather than any single finding. Its critical property is temporal: arousal is
elevated during the day as well as at night. That distinguishes insomnia
sharply from sleep deprivation, which produces daytime sleepiness, and
explains the characteristic complaint of exhaustion without the ability to
nap. A specific circuit-level account has been proposed - a locus coeruleus
that is abnormally sensitive to, or abnormally driven by, salience-network
input, remaining responsive even during REM sleep when it should be silent,
so that the overnight adaptation to emotional distress that REM sleep
normally provides fails and distress accumulates.
role: central_effector
biological_scale: ORGANISM
biological_processes:
- preferred_term: regulation of the sleep/wake cycle
term:
id: GO:0042749
label: regulation of circadian sleep/wake cycle
modifier: ABNORMAL
evidence:
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Autonomous, neuroendocrine, neuroimmunological, electrophysiological and
neuroimaging studies demonstrate increased levels of arousal in primary
insomnia during both night and daytime.
explanation: >-
Gives both the multi-modal convergence and the 24-hour character, which are
the two properties this node rests on.
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
The current review provides substantial support for the concept that
hyperarousal processes from the molecular to the higher system level play a
key role in the pathophysiology of primary insomnia.
explanation: >-
States the framework's central claim and the range of levels at which the
evidence sits.
- reference: PMID:32790576
reference_title: "Brain mechanisms of insomnia: new perspectives on causes and consequences."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
The model proposes that in people with a vulnerability to develop insomnia,
the locus coeruleus is more sensitive to-or receives more input from-the
salience network and related circuits, even during rapid eye movement
sleep, when it should normally be sound asleep.
explanation: >-
Cited as PARTIAL because the source explicitly presents this as a testable
proposed model rather than an established finding; it is the most specific
circuit-level account available and is curated as a proposal.
downstream:
- target: Failure of Sleep Initiation and Maintenance
description: >-
Arousal that persists into the sleep opportunity opposes sleep onset and
permits repeated awakenings.
causal_link_type: DIRECT
- target: Perpetuating Behavioural and Cognitive Responses
description: >-
Disturbed sleep provokes compensatory behaviour and sleep-related worry,
which are learned rather than physiological.
causal_link_type: DIRECT
- name: Perpetuating Behavioural and Cognitive Responses
description: >-
A learned arm, and the one that turns an episode into a disorder. Once sleep
has been disturbed, people respond in ways that are individually reasonable
and collectively counterproductive: extending time in bed to "catch up",
which dilutes sleep across a longer window and weakens the bed-sleep
association; napping; monitoring the clock; and developing sleep-related
worry and rumination that raise arousal precisely at bedtime. These
perpetuating factors are why chronic insomnia frequently outlives the
precipitant that started it, and - crucially - they are the specific targets
of cognitive-behavioural therapy, which is why the most effective treatment
for this disorder acts on the learned arm rather than on the physiological
one.
role: amplifier
biological_scale: ORGANISM
evidence:
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
perpetuating mechanisms including dysfunctional sleep-related behavior,
learned sleep preventing associations and other cognitive factors like
tendency to worry/ruminate
explanation: >-
Names the three components of this node - behaviour, learned association,
and cognitive factors - in the model's own terms.
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
primary insomnia may be conceptualized as a final common pathway resulting
from the interplay between a genetic vulnerability for an imbalance between
arousing and sleep-inducing brain activity, psychosocial/medical stressors
and perpetuating mechanisms
explanation: >-
Establishes the three-part structure this entry's pathophysiology follows -
vulnerability, stressor, and perpetuation - and frames the disorder as a
final common pathway rather than a single lesion.
downstream:
- target: Failure of Sleep Initiation and Maintenance
description: >-
Learned associations and sleep-related worry raise arousal at the sleep
opportunity, reinforcing the failure that produced them.
causal_link_type: DIRECT
- name: Failure of Sleep Initiation and Maintenance
description: >-
The presenting abnormality: prolonged sleep-onset latency, wakefulness after
sleep onset, early-morning awakening, or non-restorative sleep, in any
combination and typically shifting between them over time. It is a failure of
sleep against adequate opportunity, which is what separates it from
insufficient sleep syndrome - the commonest cause of unrefreshing sleep in
the population and not this disorder. A persistent discrepancy between
subjective and objective measures is characteristic, with patients
consistently reporting worse sleep than polysomnography records, and this is
a feature of the disorder rather than an artefact to be corrected: it is
consistent with the hyperarousal framework, in which cortical arousal
persists into physiologically scored sleep.
role: effector
biological_scale: ORGANISM
biological_processes:
- preferred_term: sleep
term:
id: GO:0030431
label: sleep
modifier: DECREASED
evidence:
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Primary insomnia is defined as difficulties in falling asleep, maintaining
sleep or non-restorative sleep accompanied by significantly impaired
daytime functioning in the absence of a specific physical, mental or
substance-related cause.
explanation: >-
Gives the definitional content of this node, including the requirement for
daytime impairment that distinguishes the disorder from short sleep.
downstream:
- target: Daytime Impairment and Downstream Health Risk
description: >-
Disturbed sleep with sustained hyperarousal produces daytime functional
impairment and, over time, downstream psychiatric and cardiometabolic risk.
causal_link_type: DIRECT
- name: Daytime Impairment and Downstream Health Risk
description: >-
The clinical endpoint, and the reason insomnia matters beyond the night.
Daytime impairment is a diagnostic requirement, not an optional consequence.
Beyond it, Mendelian randomisation in the large genetic study identified
causal effects of insomnia on depression, diabetes, and cardiovascular
disease - which is a stronger form of evidence than the observational
associations usually cited, because it is less vulnerable to reverse
causation, and matters most for depression, where the direction of effect has
long been contested. It should still be read as a genetic-instrument
inference and not as a demonstrated clinical effect of treating insomnia.
role: consequence
biological_scale: ORGANISM
evidence:
- reference: PMID:30804565
reference_title: "Genome-wide analysis of insomnia in 1,331,010 individuals identifies new risk loci and functional pathways."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Mendelian randomization identified the causal effects of insomnia on
depression, diabetes, and cardiovascular disease, and the protective effects
of educational attainment and intracranial volume.
explanation: >-
Provides the causal-inference evidence for the downstream risks at this
node, and the direction of effect for depression in particular.
- reference: PMID:32790576
reference_title: "Brain mechanisms of insomnia: new perspectives on causes and consequences."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Further supported by the clear mental health risks conveyed by insomnia
explanation: >-
Independently records the mental-health risk associated with the disorder,
corroborating the Mendelian randomisation result above.
phenotypes:
- category: Neurological
name: Sleep-Onset Insomnia
description: >-
Prolonged latency to sleep onset despite adequate opportunity and an
appropriate sleep environment.
phenotype_term:
preferred_term: Sleep onset insomnia
term:
id: HP:0031354
label: Sleep onset insomnia
temporality: CHRONIC
evidence:
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Primary insomnia is defined as difficulties in falling asleep, maintaining
sleep or non-restorative sleep
explanation: >-
One of the three definitional presentations; no frequency band is asserted,
since the three forms overlap and shift within individuals over time.
- category: Neurological
name: Sleep-Maintenance Insomnia
description: >-
Repeated or prolonged awakenings after sleep onset, with difficulty returning
to sleep.
phenotype_term:
preferred_term: Maintenance insomnia
term:
id: HP:0031355
label: Maintenance insomnia
temporality: CHRONIC
evidence:
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
difficulties in falling asleep, maintaining sleep or non-restorative sleep
accompanied by significantly impaired daytime functioning
explanation: >-
One of the three definitional presentations, curated with its daytime
impairment requirement; no frequency band is asserted.
- category: Neurological
name: Daytime Functional Impairment
description: >-
Fatigue, impaired attention and concentration, mood disturbance, and reduced
performance attributable to the sleep disturbance. A required criterion
rather than an associated feature, and characteristically experienced as
fatigue without sleepiness.
phenotype_term:
preferred_term: Insomnia
term:
id: HP:0100785
label: Insomnia
temporality: CHRONIC
frequency: OBLIGATE
evidence:
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
accompanied by significantly impaired daytime functioning in the absence of
a specific physical, mental or substance-related cause
explanation: >-
OBLIGATE by definition: significant daytime impairment is part of the
diagnostic definition, so every diagnosed patient has it.
treatments:
- name: Cognitive Behavioural Therapy for Insomnia
description: >-
First-line treatment, and mechanistically the best-matched: its components -
sleep restriction, stimulus control, cognitive therapy, relaxation, sleep
hygiene - map directly onto the perpetuating node, dismantling the learned
associations and compensatory behaviours rather than sedating the arousal.
Meta-analysis of randomised trials against inactive comparators shows
clinically meaningful improvements in sleep-onset latency, wake after sleep
onset, and sleep efficiency, with benefit sustained at later timepoints and
no adverse outcomes reported - a profile no hypnotic matches. Note the
trade-off the same data reveal: total sleep time improved by only about eight
minutes and not significantly, so the treatment works by consolidating and
re-associating sleep rather than by producing more of it.
therapeutic_modality: BEHAVIORAL
treatment_term:
preferred_term: Behavioral counseling
term:
id: NCIT:C181743
label: Behavioral Counseling
target_mechanisms:
- target: Perpetuating Behavioural and Cognitive Responses
treatment_effect: INHIBITS
description: >-
Directly dismantles the learned associations, compensatory time-in-bed
extension, and sleep-related worry that perpetuate the disorder.
evidence:
- reference: PMID:26054060
reference_title: "Cognitive Behavioral Therapy for Chronic Insomnia: A Systematic Review and Meta-analysis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
CBT-i is an effective treatment for adults with chronic insomnia, with
clinically meaningful effect sizes.
explanation: >-
Meta-analytic conclusion across 20 randomised trials supporting first-line
status.
- reference: PMID:26054060
reference_title: "Cognitive Behavioral Therapy for Chronic Insomnia: A Systematic Review and Meta-analysis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
SOL improved by 19.03 (95% CI, 14.12 to 23.93) minutes, WASO improved by
26.00 (CI, 15.48 to 36.52) minutes, TST improved by 7.61 (CI, -0.51 to
15.74) minutes, and SE% improved by 9.91% (CI, 8.09% to 11.73%)
explanation: >-
Cited as PARTIAL because it qualifies the effect: latency, wakefulness
after onset, and efficiency improve, while total sleep time does not
significantly increase - the consolidation-not-quantity point in the
description.
- reference: PMID:26054060
reference_title: "Cognitive Behavioral Therapy for Chronic Insomnia: A Systematic Review and Meta-analysis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Approaches to CBT-i incorporated at least 3 of the following: cognitive
therapy, stimulus control, sleep restriction, sleep hygiene, and relaxation.
explanation: >-
Enumerates the components, which is what allows the treatment to be mapped
onto the perpetuating node rather than onto the arousal node.
- name: Dual Orexin Receptor Antagonist (Suvorexant)
description: >-
A hypnotic that reduces arousal drive by blocking orexin receptors, rather
than by potentiating GABA-A as the benzodiazepine-receptor agonists do. It
acts on the arousal node, which is the node the hyperarousal framework makes
central, and is the pharmacological class best matched to that framework.
Curated with an explicit caution: its efficacy does NOT indicate an orexin
abnormality in these patients, and this entry does not conform to the orexin
module on the strength of it. It reduces sleep-onset latency and increases
sleep duration objectively and subjectively, with somnolence the commonest
adverse effect and no strong rebound or withdrawal signal.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: suvorexant
term:
id: CHEBI:82698
label: suvorexant
target_mechanisms:
- target: Persistent 24-Hour Physiological Hyperarousal
treatment_effect: INHIBITS
description: >-
Blockade of orexin receptors lowers arousal drive at the sleep opportunity,
acting on the central effector node rather than on the learned arm.
evidence:
- reference: PMID:26937493
reference_title: "Suvorexant: efficacy and safety profile of a dual orexin receptor antagonist in treating insomnia."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Suvorexant was shown to decrease sleep onset times and increase sleep
duration, whether assessed objectively by polysomnography or subjectively
by sleep diaries in primary insomnia patients.
explanation: >-
Establishes efficacy on both objective and subjective measures, which
matters in a disorder characterised by discrepancy between the two.
- reference: PMID:26937493
reference_title: "Suvorexant: efficacy and safety profile of a dual orexin receptor antagonist in treating insomnia."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Further studies are required in patients with insomnia comorbid with
depression and head-to-head studies with established hypnotics such as
zolpidem and eszopiclone.
explanation: >-
Cited as PARTIAL because it records what the evidence does not yet
establish - comparative efficacy against existing hypnotics, and
performance in the comorbid-depression population that is a large share of
real patients.
genetic:
- name: Polygenic architecture (202 loci, no established single gene)
notes: >-
Insomnia is substantially heritable but has no Mendelian form and no
established causal gene. The largest genome-wide analysis - 1,331,010
individuals - identified 202 loci implicating 956 genes through positional,
eQTL, and chromatin mapping, and the meta-analysis explained 2.6% of the
variance. Curated as an architecture rather than as a gene list because no
individual locus is established as causal and none is clinically actionable.
The informative signal is where the enrichment sits: cortical and subcortical
tissue and striatal, hypothalamic, and claustrum neurons, with considerable
genetic correlation to psychiatric traits - which is what locates the
vulnerability in emotion-arousal rather than sleep-regulatory circuits.
relationship_type: SUSCEPTIBILITY
evidence:
- reference: PMID:30804565
reference_title: "Genome-wide analysis of insomnia in 1,331,010 individuals identifies new risk loci and functional pathways."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We identify 202 loci implicating 956 genes through positional, expression
quantitative trait loci, and chromatin mapping.
explanation: >-
Establishes the scale of the polygenic architecture and the mapping methods
behind the implicated gene set.
- reference: PMID:30804565
reference_title: "Genome-wide analysis of insomnia in 1,331,010 individuals identifies new risk loci and functional pathways."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The meta-analysis explained 2.6% of the variance.
explanation: >-
Cited as PARTIAL to bound the genetic arm: 202 loci in 1.3 million people
account for a small fraction of variance, so no individual-level genetic
prediction follows and no single gene may be curated as causal.
inheritance:
- name: Complex/Multifactorial
inheritance_term:
preferred_term: Polygenic inheritance
term:
id: HP:0010982
label: Polygenic inheritance
description: >-
Substantially heritable, polygenic, with no Mendelian form. Risk arises from
many small-effect common variants interacting with early-life stress, major
life events, and perpetuating behavioural factors - the three-part
vulnerability/stressor/perpetuation structure this entry's pathophysiology
follows.
evidence:
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
the interplay between a genetic vulnerability for an imbalance between
arousing and sleep-inducing brain activity, psychosocial/medical stressors
and perpetuating mechanisms
explanation: >-
States the multifactorial architecture - genetic vulnerability plus
stressors plus perpetuation - that this inheritance block records.
diagnosis:
- name: Clinical diagnosis against explicit criteria, with a sleep diary
description: >-
Chronic insomnia disorder is a clinical diagnosis: persistent difficulty
initiating or maintaining sleep with significant daytime impairment, despite
adequate opportunity, for at least three months. A prospective sleep diary
over one to two weeks is the core instrument. Which criteria are applied
matters more here than in most disorders - see the prevalence record, where
four standard criteria sets applied to the same 21,083-person cohort gave
prevalences from 8.5% to 23.6%, the difference driven largely by whether
daytime impairment is adequately required.
evidence:
- reference: PMID:38718598
reference_title: "Prevalence of insomnia in a general adult population cohort using different diagnostic criteria: The seventh survey of the Tromsø study 2015-2016."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
When looking at each symptom, we found over half the participants
classified as having insomnia using the DSM-IV-TR and ICSD-3 criteria did
not report having impaired daytime functioning at least three days per week.
explanation: >-
Demonstrates that the daytime-impairment requirement is what separates the
criteria sets, which is why this entry curates it as an obligate phenotype
rather than an associated feature.
- name: Polysomnography only to exclude another disorder
description: >-
Polysomnography is not indicated for uncomplicated chronic insomnia and does
not establish the diagnosis. It is used to exclude a comorbid sleep disorder
- sleep-disordered breathing, periodic limb movements - when clinical
features suggest one, or when the patient has not responded to adequate
treatment. Expect a discrepancy between recorded and reported sleep if it is
performed; that gap is characteristic of the disorder rather than evidence
against it.
evidence:
- reference: PMID:19481481
reference_title: "The hyperarousal model of insomnia: a review of the concept and its evidence."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Primary insomnia is defined as difficulties in falling asleep, maintaining
sleep or non-restorative sleep accompanied by significantly impaired
daytime functioning in the absence of a specific physical, mental or
substance-related cause.
explanation: >-
The definition is clinical and exclusionary - "in the absence of a specific
physical, mental or substance-related cause" - which is what makes
polysomnography an exclusion tool rather than a diagnostic one.
prevalence:
- population: Tromso Study seventh survey, Norwegian adults aged 40-99 (DSM-5 criteria)
measure_type: POINT_PREVALENCE
prevalence_class: ABOVE_1_IN_1000
rate_per_100000: 8500.0
notes: >-
DSM-5 criteria applied to a 21,083-adult cohort. Curated as the primary
record because DSM-5 is the most restrictive of the four criteria sets and
the closest to the entity this entry curates - it requires daytime
impairment, which is what this entry treats as an obligate phenotype.
Recorded as its own record rather than as the low bound of a range: the
spread across criteria sets is definitional, not a sampling interval, and
encoding it as rate_low/rate_high would invite reading it as a confidence
interval.
evidence:
- reference: PMID:38718598
reference_title: "Prevalence of insomnia in a general adult population cohort using different diagnostic criteria: The seventh survey of the Tromsø study 2015-2016."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We found the following prevalence of insomnia: DSM-IV-TR 23.6 %, DSM5 8.5
%, ICD-10 9.9 % and ICSD-3 20.0 %.
explanation: >-
Gives all four criteria-dependent rates from a single cohort; the DSM-5
figure is the one this record carries.
- population: Tromso Study seventh survey, Norwegian adults aged 40-99 (ICSD-3 criteria)
measure_type: POINT_PREVALENCE
prevalence_class: ABOVE_1_IN_1000
rate_per_100000: 20000.0
notes: >-
The same cohort scored against ICSD-3, the sleep-medicine classification,
giving 20.0% - roughly 2.4-fold the DSM-5 figure. The difference is almost
entirely the daytime-impairment requirement: over half of those meeting
ICSD-3 or DSM-IV-TR criteria did not report impaired daytime functioning at
least three days per week. Curated alongside the DSM-5 record so the
criteria-dependence is visible as data rather than only as prose.
evidence:
- reference: PMID:38718598
reference_title: "Prevalence of insomnia in a general adult population cohort using different diagnostic criteria: The seventh survey of the Tromsø study 2015-2016."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We found the following prevalence of insomnia: DSM-IV-TR 23.6 %, DSM5 8.5
%, ICD-10 9.9 % and ICSD-3 20.0 %.
explanation: >-
Source of the ICSD-3 figure carried by this record.
- reference: PMID:38718598
reference_title: "Prevalence of insomnia in a general adult population cohort using different diagnostic criteria: The seventh survey of the Tromsø study 2015-2016."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
When looking at each symptom, we found over half the participants
classified as having insomnia using the DSM-IV-TR and ICSD-3 criteria did
not report having impaired daytime functioning at least three days per week.
explanation: >-
Identifies the daytime-impairment requirement as the source of the spread
between criteria sets, which is what the note asserts.
- population: Tromso Study seventh survey, Norwegian adults aged 40-99 (ICD-10 criteria)
measure_type: POINT_PREVALENCE
prevalence_class: ABOVE_1_IN_1000
rate_per_100000: 9900.0
notes: >-
The same cohort scored against ICD-10, giving 9.9% - close to the DSM-5
figure, and for the same reason: both require daytime consequences.
evidence:
- reference: PMID:38718598
reference_title: "Prevalence of insomnia in a general adult population cohort using different diagnostic criteria: The seventh survey of the Tromsø study 2015-2016."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We found the following prevalence of insomnia: DSM-IV-TR 23.6 %, DSM5 8.5
%, ICD-10 9.9 % and ICSD-3 20.0 %.
explanation: >-
Source of the ICD-10 figure carried by this record.
- population: Tromso Study seventh survey, Norwegian adults aged 40-99 (DSM-IV-TR criteria)
measure_type: POINT_PREVALENCE
prevalence_class: ABOVE_1_IN_1000
rate_per_100000: 23600.0
notes: >-
The same cohort scored against DSM-IV-TR, giving 23.6% - the highest of the
four and nearly three times the DSM-5 figure. Curated so that the full
criteria-dependent range is readable from structured fields rather than only
from a snippet; DSM-IV-TR is superseded, so this record documents the
historical estimate rather than a current one.
evidence:
- reference: PMID:38718598
reference_title: "Prevalence of insomnia in a general adult population cohort using different diagnostic criteria: The seventh survey of the Tromsø study 2015-2016."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We found the following prevalence of insomnia: DSM-IV-TR 23.6 %, DSM5 8.5
%, ICD-10 9.9 % and ICSD-3 20.0 %.
explanation: >-
Source of the DSM-IV-TR figure carried by this record.
- reference: PMID:38718598
reference_title: "Prevalence of insomnia in a general adult population cohort using different diagnostic criteria: The seventh survey of the Tromsø study 2015-2016."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Overall, this study suggests that insomnia prevalence may be overestimated
if daytime symptoms are not adequately included in accordance with current
guidelines.
explanation: >-
Cited as PARTIAL because it qualifies this record rather than supporting
it: the authors read the higher criteria-sets, this one included, as
overestimates.
classifications:
harrisons_chapter:
- classification_value: NEUROLOGIC
evidence:
- reference: PMID:32790576
reference_title: "Brain mechanisms of insomnia: new perspectives on causes and consequences."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
While insomnia is the second most common mental disorder, progress in our
understanding of underlying neurobiological mechanisms has been limited.
explanation: >-
Classified under the nervous-system chapter as a disorder of brain
arousal regulation; note the source's own framing as a mental disorder,
which reflects the genuine overlap this entry's vulnerability node
records.
discussions:
- discussion_id: gap_hyperarousal_framework_versus_lesion
kind: KNOWLEDGE_GAP
prompt: >-
Is hyperarousal a mechanism or a description of the disorder's measurements?
attaches_to:
- pathophysiology#Persistent 24-Hour Physiological Hyperarousal
rationale: >-
Hyperarousal organises a large and consistent body of evidence, but it is
close to being a restatement of what is measured rather than an explanation
of it: to say a patient with insomnia is hyperaroused is not far from saying
they cannot sleep. The framework earns its status from two things it does
predict - daytime as well as nocturnal elevation, and the
subjective-objective discrepancy - but it names no lesion, specifies no
causal direction, and has not generated a treatment that acts on it
specifically. The locus coeruleus / salience network model is the first
proposal specific enough to falsify, and its authors present it as such. Until
it or a rival is tested, this entry's central node should be read as the best
available organising framework rather than as a mechanism.
proposed_experiments:
- experiment_id: exp_lc_rem_responsiveness_insomnia
name: Locus coeruleus responsiveness during REM sleep in insomnia
description: >-
High-resolution functional imaging or pupillometric assay of locus
coeruleus activity during REM sleep in patients with chronic insomnia
disorder and matched controls, with salience-network connectivity and
overnight change in emotional reactivity as covariates, directly testing
the proposed model's central prediction that the locus coeruleus fails to
go offline during REM sleep.
- discussion_id: gap_subjective_objective_discrepancy
kind: KNOWLEDGE_GAP
prompt: >-
What does the persistent gap between reported and polysomnographic sleep
measure?
attaches_to:
- pathophysiology#Failure of Sleep Initiation and Maintenance
rationale: >-
Patients with chronic insomnia consistently report substantially worse sleep
than polysomnography records, and the gap is large, reproducible, and
unexplained. How it is read determines what the disorder is taken to be. If
the polysomnogram is right, the primary abnormality is one of perception and
the disorder is partly a misestimation; if the patient is right, the
polysomnogram's scoring conventions are too coarse to capture the cortical
arousal that persists within scored sleep - which is what the hyperarousal
framework predicts. The second reading also implies that trials using
polysomnographic endpoints are measuring the wrong quantity, which would
explain why treatments improve reported sleep more than recorded sleep.
proposed_experiments:
- experiment_id: exp_high_density_eeg_within_sleep_arousal
name: High-density EEG markers of within-sleep cortical arousal
description: >-
Simultaneous high-density EEG and standard polysomnography in patients with
chronic insomnia and controls, quantifying high-frequency and local
arousal activity within conventionally scored sleep epochs, and testing
whether that activity - rather than scored sleep time - accounts for the
subjective sleep estimate.