Obsessive-compulsive (OC) symptoms and schizophrenia may present, as intertwined phenomena whose relationship remains poorly understood. The purpose of this paper is to provide a detailed phenomenological description of OC symptoms in schizophrenia.

Fifty long-term patients with chronic schizophrenia or schizoaffective disorder from a continuing day-treatment program were assessed using the Structured Clinical Interview for DSM-IV and the Yale-Brown Obsessive-Compulsive Scale symptom checklist. Forty-six percent (n=23) reported clinically significant OC symptoms. Twenty-six percent (n=13) met criteria for OCD, from which three subgroups emerged: (1) patients whose OCD was unrelated to their psychotic symptoms, (2) patients whose OCD was related to, but not restricted to, their psychotic symptoms, and (3) patients whose OC symptoms existed on a continuum with their psychosis. The last group tended to incorporate their OC symptoms into delusional beliefs during the active phase of illness and shift to OCD during full or partial remissions. Eight percent met all inclusion criteria for OCD, but their OC symptoms were better accounted for by their psychosis.

We conclude that these findings support previous clinical constructs that OCD and schizophrenia are not always dichotomous disorders, but may be interconnected.

In the past decade, clozapine, risperidone, and olanzapine were marketed for the first time in the United States, and other new antipsychotic drugs are expected to follow soon. Also within the past decade, the efficacy of serotonin-reuptake inhibitors (SRIs) has been demonstrated in patients with obsessive-compulsive disorder (OCD) and the serotonin hypothesis of OCD has been articulated clearly.

The association between obsessive-compulsive (OC) symptoms and schizophrenia has been discussed in the literature for many decades. Recent studies, which have been more systematic than earlier reports and benefited from more rigorous diagnostic criteria, have generated results that contradict earlier findings. The current consensus is that OC symptoms are seen in a significant number of patients with schizophrenia, and indicate a poor prognosis. These recent studies also suggest that OC symptoms are more than just expressions of persistent schizophrenic psychosis, and that they share characteristics with obsessive-compulsive disorder (OCD). This article discusses the arguments supporting the possibility that OC symptoms are either manifestations of comorbid OCD, or are characteristics of a distinct subtype of schizophrenia.

The convergence of obsessive and schizophrenic symptoms, particularly the blending of obsessional and delusional features into complex symptoms, calls for a clarification of the relationship between obsessions and delusions, which are usually thought of as separate and distinct, even opposite entities. This brief review is a preliminary attempt to assess some of the difficult issues raised by these phenomena.

We evaluate obsessions and delusions, and how they may overlap. A patient's degree of insight has been deemed a determining factor in distinguishing between these primary symptoms. However, our review of the literature shows that a definite distinction between obsessions and delusions cannot be made solely on the basis of insight.