F51.05 – Insomnia due to other mental disorder

The ICD-10-CM code F51.05 diagnoses a patient with insomnia caused by another mental disorder. Learn what this code entails by reading this short guide.

By Matt Olivares on Aug 8, 2025.

Fact Checked by Gale Alagos.

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F51.05 diagnosis code: Insomnia due to other mental disorder

The F51.05 is an ICD code included in the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) used to designate “Insomnia due to other mental disorder.”

Insomnia is a sleeping disorder that makes it difficult to fall asleep. This difficulty is the result of numerous factors. These factors include poor sleeping habits, mental health disorders like depression and anxiety, certain medications, and even physical afflictions. In the case of this ICD-10 code, it is caused by another mental disorder besides anxiety and depression.

Is the F51.05 billable?

Yes, the F51.05 ICD-10 code is billable and can be used to designate a patient for reimbursement purposes.

Clinical information

There are two types of insomnia: primary insomnia and secondary insomnia.

Primary insomnia is often idiopathic (meaning it just happens and the cause is unknown) or is related to stress over something.

Secondary insomnia is caused by identifiable physical and mental health disorders, like depression or chronic pain.

In the case of this ICD-10 code, the insomnia falls under secondary insomnia because it is being caused by a mental health disorder.

To diagnose secondary insomnia, healthcare providers and professionals will refer to their most updated copies of the Diagnostic and Statistical Manual of Mental Disorders and International Classification of Sleep Disorders. They will base their examinations on the criteria set by both. They can also conduct Actigraphy and Polysomnography tests to check.

Once an official diagnosis has been made, the provider can treat the problem through cognitive behavioral therapy (CBT), and propose making lifestyle changes (it can be as simple as taking a hot bath before bedtime, cutting down on caffeinated drinks, cutting down on alcohol, etc.).

Synonyms include

Insomnia due to anxiety and fear
Insomnia caused by another mental disorder
Drug-related insomnia
Organic sleep disorders
Sleep deprivation
Insomnia due to neurodevelopmental disorders

Popular search terms for this ICD-10 code

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F51.05 ICD-10 code
ICD-10 F51.05
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ICD-10 code for insomnia due to other mental disorder

Other ICD-10 codes commonly used for insomnia

F51 - Sleep disorders not due to a substance or known physiological condition
F51.0 - Insomnia not due to a substance or known physiological condition
F51.09 - Other insomnia not due to a substance or known physiological condition
F51.1 - Hypersomnia not due to a substance or known physiological condition
F51.19 - Other hypersomnia not due to a substance or known physiological condition
F51.8 - Other sleep disorders not due to a substance or known physiological condition
F51.9 - Sleep disorder not due to a substance or known physiological condition, unspecified

Commonly asked questions

Yes, this ICD-10 code is billable.

You use it when your patient is confirmed to have insomnia caused by another mental disorder. This means that there is no other specific ICD-10 code for the mental disorder causing the insomnia.

Cognitive Behavioral Therapy (CBT) and lifestyle changes should help patients work through this type of insomnia. Sedatives can also be prescribed.

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