Continuity of care between physical and behavioral health providers is a problem in today s fragmented health care system. Issues of privacy often do not allow sharing of data among providers. For physical health providers and insurers, the ability to identify patients with behavioral health problems is important for care coordination and targeting of disease management resources. OBJECTIVE: Compare methods for identification of members with psychoses using medical and pharmacy claims data in a Medicaid HMO with a state-mandated behavioral health carve-out. METHODS: Medical and pharmacy claims data were reviewed for members 18 years or older identified by ICD-9CM codes 295-299.* or prescribed 90 days of antipsychotic medications during calendar year 1998. RESULTS: Of the 86,004 members with one year s continuous enrollment, 776 had one or more medical claims with a psychosis diagnosis and 2,800 had used antipsychotics. The 3,166 unique members were categorized into three groups: 410 members identified by both medical and pharmacy claims, 366 identified by medical claims only, and 2,390 identified by pharmacy claims only. Identifying psychotic members on either medical or pharmacy claims alone neglected 75% and 12% of the population respectively. CONCLUSIONS: These results suggest a majority of psychotic patients have not been recognized by the physical health provider to have psychoses, are not receiving physical as well as behavioral health services, or physical providers are not coding these diagnoses. This suggests continuity of care between the physical and behavioral health care carve-out providers is lacking. Further data analysis will be performed to assess resource use and patterns of care among these groups.