Age-of-onset of schizophrenic and obsessive-compulsive symptoms in patients with schizo-obsessive disorder

Obsessive-compulsive symptoms (OCS) are prevalent, persistent, clinically significant phenomena in schizophrenia. To facilitate the understanding of their temporal interrelationship, we assessed age-of-onset of schizophrenic and obsessive-compulsive symptoms among 133 patients admitted to Tirat Carmel Mental Health Center (Israel) during the years 1999-2010 who met DSM-IV criteria for both schizophrenic disorder and obsessive-compulsive disorder (OCD). The mean age-of-onset of the first clinically significant OCS was significantly earlier than the mean age-of onset of the first psychotic symptoms. An earlier onset of OCS was detected in men, but not in women. In sixty-four of 133 patients OCS preceded the first psychotic symptoms, in 37 patients OCS followed them, and in 32 patients OCS and psychotic symptoms occurred simultaneously. A sub-analysis of 52 first-episode schizophrenia patients revealed that OCS emerged approximately 3 years earlier than psychotic symptoms. Notably, schizo-obsessive patients had earlier mean age-of-onset of first psychotic symptoms than a comparative group of 113 non-OCD schizophrenia patients matched for age, gender and number of hospitalization. Earlier emergence of OCS than schizophrenic symptoms in schizo-obsessive patients suggests that they are independent of psychosis and are not consequent to schizophrenia. In addition, the presence of OCS seems to modify clinical features of schizophrenia accounting for earlier onset of first psychotic symptoms, however a replication of these findings is needed.