Adverse events during the perinatal period were independently associated with an increased risk of obsessive-compulsive disorder at age 40 years, based on data published Oct. 5 from a population-based cohort study of more than 2 million Swedish children.
Perinatal complications, including C-section delivery and preterm birth, have been linked to psychiatric disorders including schizophrenia, autism, and attention-deficit/hyperactivity disorder, but evidence of an impact of obsessive-compulsive disorders has not been well studied, reported Gustaf Brander of the Karolinska Institutet, Stockholm, and his colleagues.
The researchers reviewed data from 2,421,284 live singleton births in Sweden between Jan. 1, 1973, and Dec. 31, 1996. The overall prevalence of OCD was 1.3% at 40 years of age. Several perinatal factors were independently associated with an increased OCD risk: breech presentation, cesarean section delivery, gestational age of less than 32 weeks, maternal smoking during pregnancy, Apgar scores near the distress level, and both low and high birth weight (defined as 1,500-2,500 g and greater than 4,500 g, respectively).
“These findings contradict the widely held notion that, although mental disorders share genetic risk factors, the contribution of environmental risk factors is largely disorder specific,” with the exception of maternal smoking during pregnancy, the researchers wrote. In addition, the researchers found a dose-response relationship in which the risk for OCD increased with the greater number of perinatal adverse events.
“The findings are important for the understanding of the cause of OCD and will inform future studies of gene by environment interaction and epigenetics,” the researchers said. “If the finding is replication, the association between maternal smoking during pregnancy and OCD may emerge as an interesting disorder-specific risk factor for evaluation in future research,” they added.
Mr. Brander had no financial conflicts to disclose; several coauthors disclosed relationships with companies including Eli Lilly, Shire, and Medice.
Find the full study here: (JAMA Psychiatry. 2016 Oct 5. doi: 10.1001/jamapsychiatry.2016.2095).