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Understanding the difference between ICD-10 and ICD-11

Learn the difference between ICD-10 and ICD-11 so you can update diagnosis codes, stay compliant, and avoid costly claim denials.

January 29, 2026

By Dr. Juli Fraga, Psy.D

6 min read

By Dr. Juli Fraga, Psy.D

As therapists, many of us never learn the nuts and bolts of medical coding in graduate school. At first glance, those words might sound like computer programming language, so what role do they play in our jobs as therapists? 

Medical codes, such as ICD-10 codes (which stands for the International Classification of Diseases), are a tool used by all medical providers to diagnose medical conditions, including mental health conditions. While many clinicians are most familiar with using the DSM-5-TR for diagnosis, insurance companies rely on ICD-10 codes for billing and reimbursement.

In 2022, the World Health Organization (WHO) updated the ICD-10 codes with ICD-11 codes. Understanding the difference between the two can help prevent reimbursement delays from insurance companies and help you streamline your practice. 

Read on to learn more about ICD-11 codes, as well as how to incorporate them into your billing process.

Key insights

1

The ICD-11 codes include 6 additional chapters of conditions, which allow for more precise diagnoses.

2

ICD-11 codes became available for use in 2022, but it’s estimated to take years for the U.S. to fully adopt the new coding system.

What is the ICD-11?

Nearly 80 years ago, the World Health Organization (WHO) developed the ICD-6, which became the foundation for the medical coding system that’s used today. By the 1980s, Medicare began using ICD codes for insurance reimbursement. However, it wasn’t until 2015 that the U.S. Department of Health and Human Services (HHS) required medical health providers — including psychotherapists and psychiatrists — to use ICD codes for mental health diagnoses. 

The ICD-11 is the World Health Organization's latest revision to its classification of medical conditions. This iteration introduces specific diagnoses that were left out of ICD-10, as well as updates how some conditions are defined, named, and grouped to reflect current research and clinical practice. The ICD-11 removed some diagnoses, reclassified others, updated diagnostic criteria, renamed certain conditions, and reorganized entire sections, allowing therapists to provide their clients with a more accurate diagnosis. 

For example, the ICD-11 now includes a category for mental health conditions that are the result of pregnancy/childbirth, such as depression and anxiety. The new diagnosis specifier allows clinicians to accurately record a diagnosis of perinatal depression or anxiety. This example highlights how the ICD-11 includes more detailed codes. 

There are also new codes for specific diseases, conditions, and even social determinants of health, such as loneliness, which has been linked with mental health conditions like major depressive disorder. Additional examples include codes for complex PTSD, gaming disorder, and prolonged grief disorder.

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When will the U.S. use ICD-11?

Right now, the U.S. does not have a set date to implement ICD-11. The updated system is a substantial change to ICD-10, and will require the federal government — and, in turn, insurers — to adopt it. Once the federal government does put the adoption in motion, ICD-11 can begin being used in EHRs and payer systems at hospitals,mental health clinics, and beyond.

ICD codes are a HIPAA-mandated standard for electronic healthcare transactions. For ICD-11 to be used for billing, the Department of Health and Human Services (HHS) must issue a federal rule, which the Centers for Medicare & Medicaid Services (CMS) then enforces for all HIPAA-covered entities, including private insurers.

Data from the World Health Organization (WHO) shows that 132 member states and 72 countries are actively moving towards adopting the updated coding system. However, the complexity of the United States' healthcare system requires a longer transition timeline. Several sources cite 2027 as the implementation date.

The key differences between ICD-10 and ICD-11

ThemesICD-10ICD-11
Structure and organizationHierarchical and alphanumeric codes that range from A00.0 to Z99.9. Includes 22 chapters of diseases and conditionsNew structure with alphanumeric codes that range from 1A00.0 to ZZ9Z.ZZ. Encompasses 28 chapters of diseases and conditions
Coding accuracySome conditions were grouped into broad categories, such as the “F” codes like F41.9 for “unspecified anxiety disorder” Provides more detailed codes. For example, F41.9 is now coded as “anxiety and fear disorder,” and clinicians can add a specific code to indicate the exact type of anxiety
Clinical terminology Contains outdated terminology, such as calling gender incongruence “Gender Identity Disorder”Aligns with more contemporary language, such as the reclassification of Autism Spectrum Disorder or the shift to gender incongruence

The eventual impact of ICD-11

Overall, the ICD-11 improves accuracy in diagnosis. For example, consider a client with symptoms of post-traumatic stress disorder (PTSD) — such as hyperarousal, avoiding trauma triggers, and hypervigilance — who also experiences emotional dysregulation, difficulty trusting others, and dissociation. Under ICD-11, this condition can be coded as “complex PTSD,” which is a more specific diagnosis than the ICD-10 code of PTSD with an explainer of “enduring personality change after catastrophic experience.”

The specificity of these codes helps facilitate more targeted treatment planning for clinicians and care providers. For example, a client with a diagnosis of C-PTSD may benefit from a different treatment plan than a client with the exact same symptoms who was diagnosed with PTSD under the ICD-10 codes. In addition, more granular diagnoses may result in different reimbursement rates from insurance payers.

FAQs about ICD-11

Will the U.S. move to ICD-11?

Yes, the U.S. will move to ICD-11. There’s no specific date, but implementation could begin as early as 2027.

Is ICD-11 being used yet? 

Yes, the ICD-11 was introduced in 2022 and is being used outside the U.S. A complete rollout stateside will take time due to the complexities of our healthcare system. That said, any clinician can technically use the ICD-11 for diagnosis, but not for billing.

How does the code structure in ICD-11 differ from ICD-10? 

The new coding system is more detailed, easier to implement digitally, and includes updated classifications for various health conditions. The new coding system provides “clustered” codes that can be combined with a “stem” code and a “post-coordination” code. 

For example, mental health professionals can now code major depression as 6A70 for a single episode, or 6A71 for recurrent episodes. Two examples of stem codes are 6A70.0 for “single episode depressive disorder, mild,” and 6A71.4 for “recurrent depressive disorder, current episode severe, without psychotic symptoms.” 

Streamline your practice with Headway

All licensed mental health professionals who bill insurance payers will eventually use the ICD-11 to streamline the billing process, provide more granular diagnoses, and develop more robust treatment plans. Here at Headway, we provide billing and documentation tools that make it so you can spend less time on administrative work and more time caring for your clients.

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This content is for general informational and educational purposes only and does not constitute clinical, legal, financial, or professional advice. All decisions should be made at the discretion of the individual or organization, in consultation with qualified clinical, legal, or other appropriate professionals.

© 2026 Therapymatch, Inc. dba Headway. All rights reserved. No part of this publication may be reproduced without permission.

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