Individuals diagnosed with obsessive-compulsive disorder (OCD) — and even the children of those with OCD — are at significantly greater risk for developing schizophrenia and schizophrenia spectrum disorders later in life, according to a new study published in JAMA Psychiatry.
Although OCD and schizophrenia are two distinct mental disorders, with little overlap, previous research has suggested a link between the two conditions.
In the new study, lead researcher Sandra M. Meier, Ph.D., of Aarhus University, Denmark, and colleagues, analyzed data of 3 million people born between 1955 and 2006. Of the more than 16,200 people who developed schizophrenia, about 3 percent of them had a prior diagnosis of OCD.
Despite the fact that the results show an overlapping of the two disorders, said the researchers, this does not necessarily suggest that these disorders should be combined into one diagnosis.
“However, given these findings and the fact that OCD and schizophrenia co-occur with one another at a higher rate than would be expected in the general population, the phenotypes of these disorders are potentially more similar than currently acknowledged. Further research is needed to disentangle which genetic and environmental risk factors are truly common to OCD and schizophrenia or schizophrenia spectrum disorders,” researchers said.
Overall, the risk for patients with OCD is 6.9 times greater for developing schizophrenia and 5.8 times greater for schizophrenia spectrum disorders. The children of parents with OCD had 4.3 and 3.1 times higher risk respectively.
“Our results might indicate a marked need of prevention in patients with OCD, especially as [co-existing] OCD seems to implicate negative outcomes of schizophrenia,” wrote the researchers.
“Patients with schizophrenia and [co-existing] OCD are reported to have an earlier age at onset, more depressive symptoms and suicide attempts, higher hospitalization and unemployment rates, higher symptom severity, and greater disability.”
The researchers said the two conditions probably exist on a common pathway, but that further research is needed to unravel which genetic and environmental risk factors are truly common to both disorders.
OCD is a disorder in which thoughts and images chronically intrude into the mind of sufferers. People with obsessive-compulsive disorder often carry out repetitive behaviors, either physically or mentally, in an attempt to reduce the accompanying anxiety.
Schizophrenia is one of the most severe and rarest of the mental health disorders, occurring in about 1 in 100 people. It usually starts in late adolescence, and is characterized by symptoms such as hallucinations, delusions, paranoia, cognitive impairment, social withdrawal, self-neglect and loss of motivation and initiative.
Source: JAMA Psychiatry