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Chronic Insomnia / Insomnia Disorder


Insomnia disorder is characterised by self-reported frequent ‘Difficulties Initiating and/or Maintaining Sleep’ (DIMS), and daytime impairments.

Sleep can be defined as a reversible behavioural state of perceptual disengagement from, and unresponsiveness to, the environment.1 The DSM-5 criteria that define insomnia disorder are outlined below.2, American Psychiatric Association. Diagnostic and statistical manual of mental disorders (5th ed, DSM-V). 2013The American Academy of Sleep Medicine. 3rd ed. International Classification of Sleep Disorders (ICSD-3), Diagnostic and coding manual: Westchester, IL; 2014

Insomnia can be defined as an ‘acute’ (<3 months) or ‘chronic’ disorder (at least 3 months). Acute insomnia is commonly associated with an obvious underlying precipitant. However, independent psychological and behavioural insomnia perpetuating factors can develop very quickly, and may be present in many patients with acute insomnia.

Insomnia disorder’s predominant complaint of dissatisfaction with sleep quantity or quality is associated with:

  • Difficulty initiating sleep defined by sleep latency (time taken to fall asleep >30 min)
  • Difficulty maintaining sleep (wake periods >30 min) and unable to fall back to sleep
  • Early waking (termination of sleep >30 minutes before desired wake time) and unable to fall back to sleep

The insomnia disorder’s sleep difficulty is:

  • Present for at least 3 nights per week for 3 months or more
  • Occurs despite adequate opportunity for sleep
  • Causes clinically significant distress or impairment in social, occupational, educational, academic, behavioral, or other important areas of daytime functioning (fatigue, irritability, anxiety, stress, concerns and worries, impaired attention, concentration and memory, mood disturbance, headaches, pervasive malaise, GI symptoms, deterioration in work performance) (See Clinical Presentation)

The insomnia disorder’s sleep disturbance is not adequately/better explained by:

  • Another sleep-wake disorder such as:

i. Narcolepsy

ii. Breathing-related sleep disorder including obstructive sleep apnoea

iii. Circadian rhythm sleep-wake disorder

iv. Parasomnia

  • Coexisting mental disorders and medical conditions
  • Physiological effects of a substance (e.g. drug abuse, medication)

Insomnia disorder rarely improves without targeted treatment.

Patients with sub-threshold insomnia symptoms (e.g. normal or mild severity scores on the Insomnia Severity Index or Sleep Condition Indicator) should be monitored and re-assessed over time. Re-assurance to normalise night time awakenings, and education that mild insomnia symptoms normally abate after removal of the acute stressor.

Some people may experience intermittent insomnia symptoms that wax-and-wane over time. Current sleeping pill use may also ‘mask’ current insomnia symptoms and make severity appear lower than it actually is. CBTi is effective in the presence of sleeping pill use and should be considered to facilitate sleeping pill cessation.


AHI - Apnoea-Hypopnoea Index
BBTi - Brief Behavioural Therapy for Insomnia
BMI - Body Mass Index (kg/m2)
BQ - Berlin Questionnaire
CBTi - Cognitive Behavioural Therapy for Insomnia
CELL - Coblation Endoscopic Lingual Lightening
COPD - Chronic Obstructive Pulmonary Disease
CVA - Cerebrovascular Accident
CPAP - Continuous Positive Airway Pressure
CSA - Central Sleep Apnoea
DASS - Depression Anxiety Stress Scale
DBAS - Dysfunctional Beliefs and Attitudes about Sleep
DBP - Diastolic Blood Pressure
DIMS - Difficulties Initiating and/or Maintaining Sleep
DISE - Drug-Induced Sleep Endoscopy
DISS - Daytime Insomnia Symptom Scale
ENT - Ear Nose and Throat
ESS - Epworth Sleepiness Scale
FOSQ - Functional Outcomes of Sleep Questionnaire
FSH - Follicle-Stimulating Hormone
FTP - Friedman Tong Position
GP - General Practitioner
HANDI - RACGP Handbook of Non-Drug Interventions
HGNS - Hypoglossal Herve Htimulation
ISI - Insomnia Severity Index
K10 - Kessler Psychological Distress Scale
MAD - Mandibular Advancement Device
MAS - Mandibular Advancement Rplint
MBS - Medicare Benefits Schedule
MMA - Maxillomandibular Advancement Surgery
MRA - Mandibular Repositioning Appliance
ODI - Oxygenation Desaturation Index
OSA - Obstructive Sleep Apnoea
PLMD - Periodic Limb Movement Disorder
PT - Positional Therapy
PTSD - Post-Traumatic Stress Disorder
PSG - Polysomnography
QSQ - Quebec Sleep Questionnaire
REM - Rapid Eye Movement
RFTB - Radiofrequency Thermotherapy of the Tongue Base
SBP - Systolic Blood Pressure
SCI - Sleep Condition Indicator
SE - Sleep Efficiency
SF36 - Short-Form (36) Health Survey
SMILE - Submucosal Minimally Invasive Lingual Excision
SNRIs - Serotonin-Norepinephrine Reuptake Inhibitors
SOL - Sleep Onset Latency
SSRI - Selective Serotonin Reuptake Inhibitors
TFTs - Thyroid Function Tests
TIB - Time In Bed
TORS - Transoral Robotic Surgery
TST - Total Sleep Time
UPPP - Uvulopalatopharyngoplasty
WASO - Wake After Sleep Onset

Quick links


  1. Carskadon MA, et al. Monitoring and staging human sleep. Chapter 2 – Normal human sleep: an overview. In Principles and practice of sleep medicine; Kryger MH, Roth T, Dement WC (eds). St Louis: Elsevier Saunders 2011
  2. Impact of the DSM-IV to DSM-5 Changes on the National Survey on Drug Use and Health. Rockville (MD): Substance Abuse and Mental Health Services Administration (US) 2016