The work group reviewed which diagnosis codes should count a claim as behavioral health spending and considered three contested categories: traumatic brain injury (TBI), G‑codes for neurological disorders that can cause dementia, and Z‑codes used to document social determinants of health.

OCAH staff recommended excluding TBI from the behavioral health diagnosis list, saying inclusion might capture primarily medical spend and clinicians advised that behavioral symptoms related to TBI are usually coded under behavioral health diagnoses (for example, depression) that are already in the code set. Staff also proposed including F‑codes for dementia (mental disorders due to physiological conditions) but excluding G‑codes that represent underlying neurological diseases such as Alzheimer’s, on the grounds that behavioral health providers typically bill with F‑codes.

Clinicians pushed back on some of the coding assumptions. Geriatric psychiatrist Parnika (Parnika Saxena) said it would be appropriate to use G‑codes, but described barriers in practice: psychiatrists sometimes do not get paid when they submit G‑codes, so they use F‑codes because payers accept them. Primary care clinicians and others also questioned whether excluding G‑codes or TBI might undercount behavioral health services for some patients.

The group also debated Z‑codes (social determinants). OCAH noted Z‑codes cannot be used as a primary billing diagnosis on standard payment claims and would not change claims‑based expenditure totals; they could appear in encounter data used to allocate capitation. Some clinicians and stakeholders (including Parnika, Carrie and Vicky) urged collection of relevant Z‑codes because they document time‑intensive activities addressing social needs and could inform future payment reforms. Other participants, including Jeff, said adding Z‑codes to the payer submission code set would add complexity and may not materially change measured behavioral health spending.

OCAH will review the feedback and consider HPD‑based analyses of Z‑code use and dementia/TBI coding practices; staff did not commit to a final list during the meeting and said they will incorporate the discussion into the public comment draft.