A range of perinatal factors appear to be associated with higher risk for children later developing obsessive compulsive disorder (OCD), according to an article published online by JAMA Psychiatry.

Complications in the perinatal period have been associated with other psychiatric disorders. Few studies suggest perinatal complications may also play a role in OCD but the studies had weaknesses that preclude firm conclusions.

Gustaf Brander, M.Sc., of the Karolinska Institutet, Stockholm, Sweden, and coauthors examined a potential link using a population-based birth cohort of 2.4 million children in Sweden born between 1973 and 1996 and followed up through 2013. Of the 2.4 million individuals, 17,305 people were diagnosed with OCD at an average age of 23.

The authors report that independent of shared familial mitigating factors, maternal smoking during pregnancy, presenting as breech, delivery by cesarean section, preterm birth, low birth weight, being large for gestational age and Apgar distress scores were associated with a higher risk for developing OCD.

The mechanism linking OCD to perinatal factors remains to be identified.
Limitations include a study group weighted toward more severe cases that does not represent the totality of all patients with OCD in Sweden. Also, there are missing cases.

"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 study concludes.

Mr. Brander is supported by Karolinska Institutet partial funding for new doctoral students for the present study. Dr. Rydell has received FORTE grant 2015-00075 from the Swedish Research Council for Health, Working Life, and Welfare. Dr. Fernández de la Cruz has received grants from the David and Astrid Hagelén Foundation and FORTE grant 2015-00569 from the Swedish Research Council for Health, Working Life, and Welfare. Dr. Almqvist acknowledges financial support through grant 340-2013-5867 from the Swedish Research Council through the Swedish Initiative for Research on Microdata in the Social and Medical Sciences framework. Dr. Rück is supported by grant K2013-61P-22168 from the Swedish Research Council.