It is estimated that 7.8%–46.6% of patients with schizophrenia also have obsessive-compulsive symptoms (1–3). It has been suggested that obsessive-compulsive symptoms can be considered a defense against psychotic decompensation and a putative indicator of good prognosis. According to current opinion (2, 3), however, schizophrenic patients with obsessive-compulsive symptoms are more clinically disturbed, socially isolated, and treatment resistant than schizophrenic patients without obsessive-compulsive symptoms.

The majority of reports on obsessive-compulsive symptoms in schizophrenia deal with chronically ill patients. This introduces several limitations, such as the confounding effects of chronic illness, institutionalization, and chronic neuroleptic treatment.

In the present study, we sought to determine the rate of obsessive-compulsive disorder (OCD) in patients experiencing their first episode of schizophrenia. We also examined the relationship of obsessive-compulsive symptoms to schizophrenic symptoms.

The study group was drawn from the Department of First Hospitalizations of the Tirat Carmel Mental Health Center (Tirat Carmel, Israel). All consecutively admitted patients aged 18–45 years who were hospitalized from July 1997 to July 1998 for acute psychotic symptoms and who met DSM-IV criteria for schizophrenia spectrum disorders (schizophrenia, schizoaffective disorder, and schizophreniform disorder) were included. The diagnosis was reached with the best-estimate approach, which takes into account all the information available from the Structured Clinical Interview for DSM-IV Axis I Disorders, Patient Edition (SCID-P) (4), the treating clinicians, and first-degree relatives. Only patients who were drug-naive or had less than 12 weeks of lifetime antipsychotic drug exposure were included. Patients were excluded from the study if their psychotic symptoms were part of a major mood disorder or secondary to acute intoxication or withdrawal from alcohol or other substances or if they had a medical illness that could induce a psychotic episode. None of the study participants showed abnormal findings on routine physical examination and laboratory tests, including EEG, ECG, and, when appropriate, drug screening.

All patients were interviewed within the first 7 days of admission by a senior psychiatrist experienced in the field of schizophrenia and OCD (M.P.). The following rating scales for assessment of the mental condition were administered: the Scale for the Assessment of Positive Symptoms (SAPS) (5), the Scale for the Assessment of Negative Symptoms (SANS) (6), the Clinical Global Impression scale (CGI) for psychosis (7), and the Hamilton Rating Scale for Depression (8). The presence of OCD was defined according to the OCD module of the SCID-P (4) as 1) persistent, repetitive, intrusive, and distressful thoughts (obsessions) not related to the patient’s delusions or 2) repetitive goal-directed rituals (compulsions) clinically distinguishable from schizophrenic mannerisms or posturing. The Yale-Brown Obsessive Compulsive Scale (9), including the checklist of obsessions and compulsions, was administered to assess the severity of the obsessive-compulsive symptoms.

The study was approved by the Institutional Review Board of Tirat Carmel Mental Health Center, and written informed consent was obtained from all participants after they received a full explanation of the nature of the study.

Two-tailed Student’s t tests, chi-square tests, and Pearson’s correlation tests were used as appropriate to determine the statistical significance of our findings.

Fifty patients (38 men and 12 women) met the study criteria; 37 had schizophrenia, nine had schizophreniform disorder, and four had schizoaffective disorder. The mean age of the patients at admission was 25.3 years (SD=5.6), and their mean age at onset of the schizophrenic disorder was 23.5 years (SD=4.6). The mean duration of schizophrenia was 21.6 months (SD=29.6).

Seven (14%) of the patients (five with schizophrenic disorder, paranoid type; one with schizophrenic disorder, undifferentiated type; and one with schizophreniform disorder) also met DSM-IV criteria for OCD. In this subgroup, aged 20–33 years, the mean age at onset of the obsessive-compulsive symptoms was 16.6 years (SD=8.7) and the mean age at onset of the schizophrenic symptoms was 23.4 years (SD=5.9). In four of the patients with both schizophrenia and OCD, the obsessive-compulsive symptoms were evident before the occurrence of the schizophrenic symptoms; in two patients, the obsessive-compulsive symptoms occurred after the schizophrenic symptoms; and in one patient, they occurred concurrently. Obsessions were found in four patients, compulsions in six, and both obsessive and compulsive symptoms in three. The mean Yale-Brown scale score for the seven patients was 18.6 (SD=4.8). The obsessive-compulsive symptoms included contamination and sexual and aggressive obsessions as well as cleaning, ordering, checking, hoarding, and arranging rituals.

There were no differences in sex, marital status, education, age at onset of schizophrenia, and age at first admission between the schizophrenic patients with and without OCD. The patients with both schizophrenia and OCD scored significantly lower than the schizophrenic patients without OCD on the positive formal thought disorders subscale of the SAPS (mean=2.71, SD=0.49, versus mean=3.35, SD=0.92) (t=2.75; df=14.33, p<0.05) and on the affective flattening or blunting subscale of the SANS (mean=2.14, SD=0.69, versus mean=2.81, SD=0.98) (t=2.23; df=10.45, p<0.05). There were no significant between-group differences in the remaining SAPS and SANS subscale scores, or in the CGI and Hamilton depression scale scores. Within the subgroup with both schizophrenia and OCD, no correlation was noted between the total Yale-Brown scale score and either the SAPS or SANS score.

The findings of this study indicate that a substantial proportion of patients with first-episode schizophrenia also have OCD. The rate of OCD in our patients (14%) was similar to the 12.9% reported in patients with chronic schizophrenia by Fenton and McGlashan (2) but lower than the 25%–46% reported by Berman et al. (3). This discrepancy may be due to differences in diagnostic criteria, method of evaluation, chronicity of disease, and difficulties in differentiating obsessive-compulsive and schizophrenic symptoms. It is also possible, however, that the propensity of some antipsychotic agents to induce or exacerbate obsessive-compulsive symptoms (10) may account for the higher frequency of obsessive-compulsive symptoms in chronically treated schizophrenic patients. It is of note that three of the seven patients with both schizophrenia and OCD were exposed to antipsychotic medication before the initiation of the study. However, it seems unlikely that such a minimal time period (less than 12 weeks) had an impact on the diagnosis of comorbid OCD.

Alternatively, the obsessive-compulsive symptoms may be part of the natural course of schizophrenia in a subset of patients, in view of the fact that the two disorders apparently involve a dysregulation of common interacting neurotransmitter systems (e.g., serotonin/dopamine) and neuronal circuits. It is noteworthy that Eisen et al. (1), using the same diagnostic criteria and method of evaluation as we did, reported a lower frequency of OCD (7.8%) in patients with chronic schizophrenia. Our findings of a lack of correlation between obsessive-compulsive symptoms and either positive or negative schizophrenic symptoms are consistent with those of Berman et al. (3), who hypothesized that obsessive-compulsive symptoms are independent of schizophrenic symptoms.

Furthermore, the lesser severity of the formal thought disorders and affective blunting in the patients with both schizophrenia and OCD than in the schizophrenic patients without obsessive-compulsive symptoms may indicate a "protective" effect of the obsessive-compulsive symptoms on psychotic disintegration, at least during the earlier stages of schizophrenia.

The conclusions of the present study are limited by the lack of information on the reliability and validity of the DSM-IV OCD diagnosis for the schizophrenic population, small number of patients studied, cross-sectional nature of the study, inclusion of only hospitalized first-episode psychotic patients, and lack of follow-up for confirmation of the stability of the diagnosis of the schizophrenia-spectrum disorders and OCD as well as an evaluation of prognostic significance. Additional investigations are needed to better define the longitudinal disease course, treatment strategies, and outcome of first-episode schizophrenic patients with OCD.

Received Jan. 4, 1999; revised April 12, 1999; accepted April 16, 1999From the Research Unit, Tirat Carmel Mental Health Center, Tirat Carmel; the Faculty of Medicine, Israel Institute of Technology (Technion), Haifa; the Department of Statistics and Operations Research, Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv; the Geha Psychiatric Hospital and Laboratory of Biological Psychiatry, Felsenstein Medical Research Center, Beilinson Campus, Petah Tiqva; and the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. Address reprint requests to Dr. Weizman, Research Unit, Geha Psychiatric Hospital, P.O. Box 102, Petah Tiqva 49100, Israel; rweizma@ibm.net (e-mail).Supported by the Sarah and Moshe Mayer Foundation for Research, Geneva and Tel Aviv.