Hypersomnia due to other mental disorder

This diagnosis code signifies excessive daytime sleepiness or prolonged nighttime sleep that is directly attributable to an underlying psychiatric condition. The hypersomnia is not better explained by another sleep disorder, medical condition, or substance use. It represents a secondary sleep disturbance stemming from a primary mental health diagnosis.

Apply this code when a patient presents with significant hypersomnia symptoms, and a thorough evaluation confirms a causal link to a diagnosed mental disorder such as major depressive disorder, bipolar disorder, or schizophrenia. Documentation should clearly state the psychiatric diagnosis and the clinician's assessment that the hypersomnia is a direct manifestation or complication of that mental health condition.

• Always sequence the underlying mental disorder as the primary diagnosis, followed by this code.
• Ensure documentation explicitly links the hypersomnia to the specific mental disorder; avoid using this code for hypersomnia of unknown origin or due to other medical causes.
• Differentiate from other hypersomnia codes (e.g., F51.11 Primary Hypersomnia, G47.1x Narcolepsy) by confirming the etiology is a mental disorder.