Epidemiological and clinical relevance of insomnia diagnosis algorithms according to the DSM-IV and the International Classification of Sleep Disorders (ICSD)

Abstract

Background: Although the epidemiology of insomnia in the general population has received considerable attention in the past 20 years, few studies have investigated the prevalence of insomnia using operational definitions such as those set forth in the ICSD and DSM-IV, specifying what proportion of respondents satisfied the criteria to reach a diagnosis of insomnia disorder.

Methods: This is a cross-sectional study involving 25,579 individuals aged 15 years and over representative of the general population of France, the United Kingdom, Germany, Italy, Portugal, Spain and Finland. The participants were interviewed on sleep habits and disorders managed by the Sleep-EVAL expert system using DSM-IV and ICSD classifications.

Results: At the complaint level, too short sleep (20.2%), light sleep (16.6%), and global sleep dissatisfaction (8.2%) were reported by 37% of the subjects. At the symptom level (difficulty initiating or maintaining sleep and non-restorative sleep at least 3 nights per week), 34.5% of the sample reported at least one of them. At the criterion level, (symptoms+daytime consequences), 9.8% of the total sample reported having them. At the diagnostic level, 6.6% satisfied the DSM-IV requirement for positive and differential diagnosis. However, many respondents failed to meet diagnostic criteria for duration, frequency and severity in the two classifications, suggesting that multidimensional measures are needed.

Conclusions: A significant proportion of the population with sleep complaints do not fit into DSM-IV and ICSD classifications. Further efforts are needed to identify diagnostic criteria and dimensional measures that will lead to insomnia diagnoses and thus provide a more reliable, valid and clinically relevant classification.

Figure 1

Distribution of mental disorders among insomnia subjects These rates represent the association between mental disorders and insomnia complaints regardless of the final diagnostic issue (positive diagnosis).

Figure 2

DSM-IV Sleep-EVAL decision tree

Diagram 1

Overlapping between sleep complaints, insomnia symptoms and DSM-IV diagnoses in the general population DSM-IV Insomnia diagnoses: Primary insomnia; Substance-induced sleep disorder, insomnia type; Insomnia related to another mental disorder; Sleep disorder due to a general medical condition, insomnia type; Dyssomnia not otherwise specified.

Diagram 2

Overlapping between sleep complaints, insomnia symptoms and ICSD diagnoses in the general population ICSD Diagnoses used: idiopathic insomnia; psychophysiological insomnia; Insufficient sleep syndrome; Mood disorder associated with sleep disturbances; Panic disorder associated with sleep disturbances; Anxiety disorder associated with sleep disturbances; Circadian rhythm disorders; Obstructive sleep apnea syndrome; Periodic limb movement disorder; Restless legs syndrome; environmental sleep disorder; sleep-onset association disorder; nocturnal eating (drinking) syndrome; hypnotic, stimulant or alcohol-dependent sleep disorders.