ICD-10 Code F51 – Sleep disorders not due to a substance or known physiological condition (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F51 – Sleep disorders not due to a substance or known physiological condition
What it is
F51 identifies nonorganic sleep disorders, meaning the sleep problem is not caused by a substance, medication, or a known physical condition. Use it for clinically documented sleep disturbances such as insomnia or related nonorganic sleep complaints.
Clinical signs
Clinical features vary; refer to documentation. Common findings include difficulty falling asleep, staying asleep, or having nonrestorative sleep, with daytime impairment when noted.
When to use this code
Use F51 when the record clearly documents a sleep disorder and the provider does not link it to a substance or a known physiological cause. This code may apply when the diagnosis is nonorganic insomnia or another specified nonphysiological sleep disorder. Check documentation for the exact subtype.
Do not use for
Do not use F51 if the sleep problem is due to medication, alcohol, another substance, or an identified medical condition. Also avoid it when the chart supports a more specific sleep disorder code.
Coding tip
Confirm whether the provider documented a specific subtype under F51 before assigning the code.