Are children of married first cousins at increased risk of common mood disorders, psychoses?

Bottom Line: Being a child of married first cousins was associated with a higher likelihood of receiving medicine for common mood disorders and psychoses.

Why The Research Is Interesting: About 1 in 10 children worldwide have consanguineous parents, which is the union of two people related as second cousins or closer, despite genetic concerns. The most commonly reported form of such consanguineous partnerships is between first cousins.

Who and When: 363,960 individuals born in Northern Ireland between 1971 and 1986 and alive and living in Northern Ireland in 2014

What (Study Measures): The degree to which parents were related was assessed from questions asked shortly after a child's birth; receipt of psychotropic medication in 2010 to 2014 was used to estimate potential mental ill health, with the receipt of antidepressant or anti-anxiety medicine as an indicator of mood disorders and antipsychotic medications as an indicator of psychoses

How (Study Design): This was an observational study. Because researchers were not intervening for purposes of the study they cannot control natural differences that could explain the study findings.

Authors: Aideen Maguire, Ph.D., of Queen's University Belfast, United Kingdom, and coauthors

Results: Of 363,960 individuals, 0.2 percent (609) were born to consanguineous parents. When taking into account factors associated with poor mental health, children of first-born cousins were more likely to be in receipt of antidepressant or anti-anxiety and antipsychotic medicines than children of nonreleated parents.

Study Limitations: Information limitations of the data include prescription data without accompanying diagnosis codes or indications for use.

Related Material: The editorial, "Consanguinous Marriage and the Psychopathology of the Progeny of First-Cousin Couples," by Alison Shaw, M.A., D.Phil., of the University of Oxford, United Kingdom, also is available on the For The Media website.

For more details and to read the full study, please visit the For The Media website.

(doi:10.1001/ jamapsychiatry.2018.0133)

Editor's Note: The article includes funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

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