ICD-10 Code F44.9: Dissociative and conversion disorder, unspecified

Key Takeaways

F44.9 is a valid billable ICD-10-CM code for 2026, covering dissociative and conversion disorder when no specific subtype can be identified.

Use F44.9 only after ruling out more specific F44.x codes such as F44.0 (dissociative amnesia) or F44.4 (conversion disorder with motor symptom or deficit).

The ICD-9-CM equivalent is 300.15 (Dissociative disorder or reaction, unspecified); include this crosswalk in legacy billing reconciliations.

Pabau’s mental health EMR supports structured clinical documentation and claims management workflows that help mental health practices bill F44.9 accurately.

ICD-10 code F44.9 covers dissociative and conversion disorder, unspecified — a billable ICD-10-CM diagnosis used when a patient’s presentation is consistent with the F44 category but does not clearly align with any specific subtype. This reference guide explains the code’s billable status, synonyms, F44 hierarchy, ICD-9 crosswalk, DSM-5 alignment, and documentation requirements to support accurate reimbursement in mental health practices.

F44.9: Definition and clinical description

F44.9 is the ICD-10-CM code for dissociative and conversion disorder, unspecified. It is assigned when a patient presents with symptoms consistent with the F44 category but the clinical picture does not align clearly with any specific diagnosis within that category.

Dissociative disorders involve a disruption in the normal integration of consciousness, memory, identity, emotion, perception, behavior, and sense of self. Conversion disorder, also known as functional neurological symptom disorder (FND), refers to neurological symptoms such as weakness, seizures, or sensory disturbances that have no identifiable organic neurological cause.

When a patient’s presentation does not fit a more precise subcategory, F44.9 is the appropriate catch-all code, provided documentation supports the clinical rationale.

Billable status and coding notes for F44.9

F44.9 is a billable, specific ICD-10-CM code valid for the fiscal year 2026. It may be used for reimbursement purposes on claims submitted to Medicare, Medicaid, and commercial insurers. For accurate ICD-10 diagnosis coding, a billable code must reach the highest level of specificity the clinical record supports.

F44.9 sits at the terminal node of the F44 category. Because it carries the “unspecified” qualifier, payers may request medical necessity documentation before processing the claim. Some commercial insurers scrutinize unspecified codes and may generate additional information requests or denials when documentation does not clearly explain why a more specific code could not be assigned.

Practices billing wraparound behavioral health services alongside F44.9 may also reference HCPCS Code H2015 for comprehensive community support services billing requirements.

• Code system: ICD-10-CM (US Clinical Modification)
• Code: F44.9
• Full description: Dissociative and conversion disorder, unspecified
• Billable/specific: Yes
• 2026 status: Valid for submission
• Parent block: F40-F48 (Anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders)
• Chapter: F01-F99 (Mental, Behavioral and Neurodevelopmental disorders)

Per CMS ICD-10-CM coding guidance, coders should assign the most specific diagnosis code the documentation supports. F44.9 is appropriate only after considering whether a more precise F44.x code applies.

Applicable synonyms and “includes” notes

Several clinical terms map to F44.9 through the ICD-10-CM “Applicable To” annotations. Coders and clinicians may encounter these terms in legacy records, DSM-5 language, or payer correspondence.

The term “acute hysterical psychosis” reflects older psychiatric nomenclature. When it appears in historical records, F44.9 is the current ICD-10-CM equivalent. Clinicians should use contemporary DSM-5 diagnostic language in current clinical notes rather than these legacy terms.

F44 category hierarchy: F44.9 in context

F44.9 is the residual code within the F44 category. Understanding the full hierarchy helps coders select the correct specific code before defaulting to the unspecified option. The WHO ICD-10 browser provides authoritative navigation of the full classification structure.

Before assigning F44.9, review each specific code in this table against the patient’s documented symptoms. A patient with documented episodic memory loss without identified cause maps to F44.0, not F44.9. A patient with non-epileptic seizures (psychogenic non-epileptic seizures, PNES) may fit F44.5. Only when no specific subtype is supportable does F44.9 become the correct choice.

For related mental health diagnoses outside the F44 category, depersonalization-derealization disorder is coded to F48.1, and guidance on adjacent diagnostic code references covers related disorder codes that commonly appear alongside dissociative presentations.

ICD-9-CM crosswalk for F44.9

Practices transitioning legacy claims or reconciling pre-2015 records need the ICD-9-CM equivalent. F44.9 maps to ICD-9-CM code 300.15.

This is an approximate crosswalk. The ICD-9 code 300.15 covered a broader range of dissociative presentations than what current ICD-10-CM subcategories now distinguish. When conducting payer audits or appeals on legacy claims, note that the two code sets do not map with full clinical precision.

For reference on how similar transitions affected other diagnostic categories, see the ICD-10 code for assault by unspecified means, which illustrates how ICD-9 to ICD-10 restructuring affects code mapping.

Additional context on how ICD-9 to ICD-10 transition data appears in Medicare claims records can assist with retroactive billing reconciliation.

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DSM-5 alignment and clinical context for F44.9

The American Psychiatric Association’s DSM-5 uses different terminology and organizational structure from ICD-10-CM, but the two systems are mapped for billing purposes. Understanding the relationship helps clinicians write documentation that supports accurate coding.

In DSM-5, what ICD-10-CM classifies within F44 is largely captured under two primary categories: dissociative disorders (including dissociative identity disorder, dissociative amnesia, and depersonalization-derealization disorder) and somatic symptom and related disorders (which includes functional neurological symptom disorder, the DSM-5 equivalent of conversion disorder).

The ICD-10 code F44.9 most closely corresponds to DSM-5 presentations of functional neurological symptom disorder, unspecified, or dissociative disorder, other specified or unspecified.

For practitioners working in psychiatry EMR software environments, the DSM-5 diagnosis should appear in the clinical note alongside the ICD-10-CM code used for billing. Payers require the ICD-10-CM code on the claim; the DSM-5 diagnosis belongs in the clinical record as supporting documentation.

Using crisis intervention strategies and structured clinical frameworks during assessment helps ensure the presenting symptom profile is fully documented before assigning F44.9.

When F44.9 is clinically appropriate

F44.9 fits presentations where dissociative or conversion symptoms are clearly present but cannot be categorized further because the symptoms are mixed, early, or insufficiently differentiated at the time of the encounter. Three common scenarios include:

• A first-episode presentation where further observation is needed before confirming a specific subtype
• A patient presenting with a combination of amnesia, identity disturbance, and functional neurological symptoms that spans multiple specific codes
• An established patient whose presentation has changed and no longer aligns with the previously assigned specific code

Structured screening tools can help narrow the presentation before an unspecified code is assigned. Pabau’s Internet Addiction Test template is one example of a standardized instrument that captures behavioral symptom detail during intake for related presentations.

F44.9 should not become the default choice simply because a more specific code requires more detailed documentation. If a specific F44.x code is clinically supportable, use it and document accordingly.

Clinical documentation requirements for F44.9

Payer scrutiny of unspecified codes is high. Documentation supporting F44.9 must demonstrate that a dissociative or conversion disorder is present and that no specific subtype could be assigned at the time of the encounter. A strong clinical record for F44.9 typically includes:

• Presenting symptoms: Specific description of the dissociative or conversion symptoms observed, including onset, frequency, duration, and functional impact
• Rule-out documentation: Evidence that organic neurological or medical causes were considered and excluded through history, examination, or appropriate investigations
• Specificity rationale: A brief clinical statement explaining why a more specific F44.x code was not assigned (for example, “symptom profile spans both amnestic and sensory features and does not isolate to a single F44 subtype”)
• DSM-5 diagnostic language: Where applicable, reference the relevant DSM-5 category to provide additional clinical context for reviewers
• Treatment plan and medical necessity: Documentation of how the diagnosis informs the proposed treatment plan, supporting medical necessity for billed services

Using a psychiatric evaluation template during the initial assessment helps capture the clinical elements that payers expect when an unspecified code is submitted. Reviewing eating disorder worksheets for recovery can also provide a reference for structured symptom documentation frameworks used in mental health settings.

Structured notes reduce the risk of additional documentation requests and support cleaner first-pass claims. SOAP notes for clinical documentation provide a proven format for organizing these details systematically.

The CDC/NCHS ICD-10-CM web tool allows practitioners to verify the current-year validity of F44.9 and review any annual tabular list updates that may affect coding requirements.

Pabau’s digital intake forms allow mental health and psychiatry practices to build structured intake workflows that capture the clinical detail needed to support F44.9 at the time of the encounter.

Related ICD-10 codes to consider alongside F44.9

Dissociative presentations rarely occur in clinical isolation. Coders and clinicians should be aware of adjacent codes that may apply as additional diagnoses or that may be more appropriate than F44.9 in specific presentations.

Practices using psychology practice software with integrated coding support can configure code selection workflows that prompt clinicians to review the full F44 hierarchy before submitting F44.9. Reviewing related ICD-10 unspecified code documentation patterns can offer useful context for building these review workflows.

Practices coding across specialties encounter similar specificity requirements elsewhere in ICD-10-CM. ICD-10 Code G14 (postpolio syndrome) and ICD-10 Code M31.9 (necrotizing vasculopathy, unspecified) both require the same rule-out documentation discipline as F44.9 before an unspecified code is billed.

Claims management workflows in Pabau’s claims management software can help practices flag common denial patterns for unspecified codes and route F44.9 claims through an additional documentation review step before submission.

Conclusion

F44.9 covers dissociative and conversion presentations that do not yet meet criteria for a specific subtype. Billing staff and clinicians must ensure documentation actively supports the “unspecified” designation rather than defaulting to it.

Pabau’s mental health and psychiatry practice management platform supports structured clinical documentation, streamlined practitioner workflows, and integrated claims management workflows that help practices submit F44.9 claims with the documentation strength payers expect.

For practitioners billing injectable treatments alongside mental health services, the HCPCS Code J2350 ocrelizumab billing guide and the HCPCS code J9173 durvalumab billing guide illustrate how Pabau supports multi-specialty billing workflows. To see how Pabau handles mental health billing end to end, book a demo.

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