ICD-10 Code F02.A18 – Dementia in other diseases classified elsewhere, mild, with other behavioral disturbance (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F02.A18 – Dementia in other diseases classified elsewhere, mild, with other behavioral disturbance
What it is
This code identifies mild dementia caused by another underlying disease, with behavioral disturbance such as agitation, mood change, or similar noncognitive symptoms. Use it when the dementia is documented as secondary to a separate condition.
Clinical signs
Expect mild cognitive decline with preserved basic function, plus a behavioral problem documented by the clinician. Clinical features vary; refer to documentation for the specific behavioral disturbance and underlying disease.
When to use this code
Use F02.A18 when the record states dementia is due to another disease and the provider documents it as mild with other behavioral disturbance. You should also code the underlying condition that caused the dementia, when instructed by the record and coding rules.
Choose this code for cases where the behavioral issue is part of the dementia diagnosis, not a separate psychiatric disorder. Check documentation if severity, cause, or behavioral features are unclear.
Do not use for
Do not use this code for dementia without a documented behavioral disturbance or when the dementia is not linked to another disease. Do not assign it if the chart does not support mild severity or the secondary cause.
Coding tip
Always capture both the underlying disease and the dementia severity before assigning F02.A18.