Dolores Malaspina MD, MS, MSPHPROFESSOR | Psychiatry, Neuroscience, Genetics and Genomic SciencesIcahn School of Medicine at Mt SinaiDepartment of PsychiatryNew York, NY 10128, USA

Brief Sexual Contact Between Parents Linked to Greater Risk of Schizophrenia Interview with:

Dolores Malaspina MD, MS, MSPHPROFESSOR | Psychiatry, Neuroscience, Genetics and Genomic SciencesIcahn School of Medicine at Mt SinaiDepartment of PsychiatryNew York, NY 10128, USA

Dr. Malaspina

Dolores Malaspina MD, MS, MSPH
Professor or Psychiatry, Neuroscience,
Genetics and Genomic Sciences
Icahn School of Medicine at Mt Sinai
Department of Psychiatry
New York, NY 10128, USA What is the background for this study? What are the main findings?

Response: Schizophrenia is a severe disorder that presents in late adolescence or early adulthood with declining function, social withdrawal and psychotic symptoms such as auditory hallucinations and fixed false beliefs. It is a common condition, affecting 1% of the population, which can be not yet be prevented or cured. Its causes are still puzzling.

Evidence from many different research approaches now suggests that an overactive immune system plays some role in causing schizophrenia, but the origins of the immune dysfunction are not known.

We considered that too brief a period of sexual contact between parents could cause immune activation in offspring and thus be a risk factor for schizophrenia.

With repeated sexual contact the maternal immune system develops tolerance to genetic material from the father. Otherwise, inflammatory processes may restrict the placental blood supply between the fetus and mother.

. How did you study the duration of parental sexual contact before a pregnancy and separate this from other risk factors?

Response: We found that the risk of having an offspring with schizophrenia was 50% higher for offspring born within two years of their parent’s marriage and 38% higher at 3 years of marriage, compared to longer married parents.

An independent contravening risk was related to advancing paternal age, which increased the offspring schizophrenia risk by 34% for each 5 years.

While offspring risks related to parental psychiatric conditions were separate from durations of marriage and paternal age, the combination of shorter marriage duration and older paternal age explained all of the risk that had appeared to be carried by later marrying fathers. Couples who married later in life understandably had children sooner. What should readers take away from your report?

Response:  Insufficient maternal exposure to paternal antigens before pregnancy may increase offspring the offspring risk for schizophrenia and possibly other inflammatory or metabolic conditions.

Very few data sets have actual information of the length of time that parents had sexual relationships before a pregnancy, but over 97 percent of couples were married in this study and information had been abstracted from the birth certificates.

Accounting for this factor strengthens the effect of advancing paternal age on offspring schizophrenia risk but negates the effects of later marriage ages of father. Later marriages are secular effects and not evidence that the man harbors a social deficit related to schizophrenia. Is there anything else you would like to add?

Response: Replication studies are needed that assess utero-placental blood flow in pregnancy and conduct long term follow up studies. 


Schizophrenia Research
Available online 8 March 2019
Short duration of marriage at conception as an independent risk factor for schizophrenia

DoloresMalaspina, ThorstenKranzbcKarineKleinhaus, SulaimaDaboul, KarenRothma CaitlinGilma, fMaraGetz, SusanHarlap, YechielFriedlander

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Last Updated on April 25, 2019 by Marie Benz MD FAAD