Temporal sequence of clinical manifestation in schizophrenia with co-morbid OCD: Review and meta-analysis

Obsessive-compulsive disorder (OCD) is often a comorbidity in schizophrenia (SCZ), but little is known about whether OCD emerges before or after a diagnosis of SCZ in the absence of atypical antipsychotic medications. The authors analyzed data from clinical studies reporting the temporal sequence of OCD and SCZ in comorbid patients to determine if there was a significant statistical difference between the mean ages of onset in both disorders and the percentage of patients diagnosed with OCD before SCZ. A MEDLINE search was conducted using the keywords “OCD” and “Schizophrenia.” Studies were assessed for the presence of data regarding the ages of onset of patients comorbid with both disorders as well as the number of patients in each study diagnosed with OCD first, SCZ first, or both disorders concurrently. A meta-analysis was performed to test the a priori hypothesis that OCD is diagnosed before SCZ in patients who are comorbid with both disorders. There was no statistically significant difference in the unstandardized difference in the mean age of onset of OCD and SCZ. A strong trend in the data exists suggesting that the onset of OCD precedes SCZ. Future prospective studies with larger sample sizes are warranted.