Hierarchical diagnosis in chronic schizophrenia: a clinical study of co-occurring syndromes.
Co-occurring or associated psychiatric syndromes (APS) such as depression, obsessive-compulsive disorder (OCD), and panic disorder have largely been hidden from view by exclusion rules that prohibit their being diagnosed in the presence of schizophrenia. This article presents data from a clinical study of APS in chronic schizophrenia and reviews the relevant literature. Thirty-seven chronic schizophrenia patients consecutively admitted to a day program were administered the Structured Clinical Interview for Diagnosis for DSM-IV and the Yale-Brown Obsessive Compulsive Scale symptom checklist. Exclusion rules prohibiting the diagnosis of APS were bypassed. Eighteen patients (48.6%) had one or more APS. Ten patients (27%) had major depression. Eleven (29.7%) met criteria for OCD. Four patients (10.8%) met criteria for panic disorder. These findings suggest that APS may be common in chronic schizophrenia and that there is a need to study these syndromes' clinical validity, including their treatability. A research plan to study the validity of these syndromes further is discussed.