ICD-10 Code F51.0 – Insomnia not due to a substance or known physiological condition (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F51.0 – Insomnia not due to a substance or known physiological condition
What it is
F51.0 identifies insomnia that is not caused by a substance, medication, or an identifiable medical condition. Use it when the record supports a primary sleep problem with difficulty sleeping.
Clinical signs
Common findings include trouble falling asleep, staying asleep, or waking too early, with daytime impact such as fatigue or poor concentration. Clinical features vary; refer to documentation.
When to use this code
Use F51.0 when the clinician documents insomnia as the diagnosis and does not link it to drugs, alcohol, or a known physiologic disorder. You may also use it when the note describes chronic sleep disturbance without another cause. Check documentation if another sleep disorder is suspected.
Do not use for
Do not use this code when insomnia is documented as due to a substance, medication, or a medical condition. Avoid it if the chart supports another specific sleep disorder instead.
Coding tip
Confirm that the provider has ruled out substance-related or condition-related causes before assigning F51.0.