ICD-10 Code F34.0 – Cyclothymic disorder (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F34.0 – Cyclothymic disorder
What it is
Cyclothymic disorder is a chronic mood condition with recurring periods of hypomanic symptoms and depressive symptoms that do not meet full criteria for hypomanic or major depressive episodes. You code it when documentation identifies this specific bipolar-spectrum disorder.
Clinical signs
Clinical features include long-term mood fluctuation, with brief ups and downs, increased energy or activity at times, and periods of low mood or reduced interest. Clinical features vary; refer to documentation.
When to use this code
Use F34.0 when the provider documents cyclothymic disorder or cyclothymia. It may also apply when the record clearly describes persistent mood instability meeting this diagnosis, but not full bipolar or major depressive episodes. Check documentation if the wording is unclear.
Do not use for
Do not use this code for bipolar I or bipolar II disorder, major depressive disorder, or transient mood changes without a documented chronic pattern. Do not assume the diagnosis from symptoms alone.
Coding tip
Confirm the exact psychiatric diagnosis in the assessment, because similar mood symptoms can map to different ICD-10-CM codes.