December 29, 2014
By Rob Goodier
NEW YORK (Reuters Health) - Patients with obsessive compulsive disorder appear to have a higher risk for schizophrenia, bipolar and schizoaffective disorders as well, and the same is true for their relatives - even their grandparents and cousins, according to a sweeping new study of more than one million Swedes over the course of 40 years.
The results imply an etiological relationship between the disorders that could inform clinical practice and efforts to find linked genes, wrote Dr. David Mataix-Cols of Karolinska Institutet in Stockholm, Sweden, and his colleagues online December 15 in Schizophrenia Bulletin.
In their population-based, longitudinal study, an OCD diagnosis was linked to a 12-fold higher risk for schizophrenia and 13-fold higher risk for bipolar and schizoaffective disorders.
The risks are lower, but still higher than in the general population, for relatives of OCD patients who don't themselves have OCD. Risk ratios range from 1.5 to 1.9 for parents, children and siblings and 1.2 to 1.4 for grandparents, grandchildren, uncles, aunts, nieces, nephews, and cousins.
For OCD patients in the study, the risk of incurring a new diagnosis of schizophrenia was three-fold higher within a median of 2.4 years from the time their OCD was first diagnosed. For schizoaffective disorder, the risk was five-fold higher within 1.8 years of the OCD diagnosis, and for bipolar disorder the risk was 12-fold higher within 2.7 years.
One factor appeared to reduce the risk of a bipolar diagnosis: in a subset analysis of OCD patients who were treated in 2005, controlling for selective serotonin reuptake inhibitors reduced the likelihood of developing bipolar disorder to a risk ratio of 8.8.
"If the link between SSRI treatment and bipolar is confirmed, clinicians should use these drugs with great caution and/or consider available alternatives, (such as cognitive behavioral therapy), for OCD. It will be important for future research to establish which OCD patients are at risk of SSRI-induced mania and this is where efforts are heading right now," Dr. Mataix-Cols told Reuters Health by email.
Schizophr Bull 2014.
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