Table 3.
Classification of insomnia: Important featuresa
| Features | Classification | Clinical note(s) | Further classification or notes |
|---|---|---|---|
| Duration of symptoms | |||
| Acute/Short-term (ICD-3) | Symptoms last < 3 months | Typically lasts 1 night to a few weeks. May result from illness or a circadian rhythm disturbance such as jet-lag | |
| Chronic (ICD-3)/Insomnia disorder (DSM-5) | Symptoms last > 3 months | Usually trouble sleeping is reported 3+ nights for > 3 months | |
| Timing | |||
| Onset | Falling asleep takes > 30 min | ||
| Maintenance | Interruptions lasting more than 30–45 min are experienced during the night | ||
| Early termination | Waking earlier than intended & unable to resume sleep | ||
| Severity | |||
| Mild | Almost nightly complaint | little or no impairment on social or occupational functions | |
| Moderate | Nightly complaint | Mild-moderate impairment on social/occupational functions | |
| Severe | Nightly complaint | Severe impact on social/occupational functions | |