A study links placenta to greater risk of schizophrenia for people who may inherit it and at the same time, were conceived with prenatal conditions.
Experts have already established in the past that genetics is responsible for 60 to 70 percent of a person's risk for schizophrenia. Simply put, the condition is hereditary.
It has already been established that complications during pregnancy increase the risk for the babies to develop schizophrenia later in life, particularly if hereditary conditions made them already vulnerable to the condition. For the latter case, however, experts were not sure why it is happening.
Placenta As Probable Culprit
Now, a team led by Daniel Weinberger of the Lieber Institute for Brain Development in Baltimore is pointing at the placenta as the most probable culprit for this ambiguity.
The team found that when the genes responsible for schizophrenia interacted with the cells that cause the complicated pregnancy, the risk of the person having schizophrenia is at least fivefold higher than a person who may simply inherit the condition.
The team further said that this discovery might also be true to other neurodevelopmental disorders such as ADHD, autism, and Tourette's syndrome.
Placenta And Mental Illness
The international team of researchers discovered that almost one-third of the genes responsible for schizophrenia are found in the placenta. However, these genes may only result to fully developed mental disorder for a person when his or her mother contracted a disease during pregnancy.
Such pregnancy complications may include preeclampsia or extremely high blood pressure in the mother, abnormal fetus growth, placenta blocking the birth canal, unexpected Cesarea section, and premature breaking of the water before labor.
"For the first time, we have found an explanation for the connection between early life complications, genetic risk, and their impact on mental illness and it all converges on the placenta," Weinberger said.
To conduct their study, the team analyzed medical records of more than 2,800 adult individuals, 2,038 of which had schizophrenia. The individuals observed also belonged to different ethnic backgrounds. They came from the United States, Europe, and Asia. They underwent genetic testing and were interviewed regarding obstetrical history.
The findings published in Nature Medicine may significantly help experts to accurately predict who is at risk of mental illness as early as possible. The study could help doctors to develop medical interventions that could increase the health of the placenta for cases where fetuses are susceptible to hereditary schizophrenia.
Males And Mental Disorders
The researchers noted that experts were also baffled as to why schizophrenia, ADHD, autism, Tourette's syndrome, dyslexia, and other behavioral disorders seemed to appear 2-4 times greater in males than in females.
Another observation in the study is that schizophrenia genes become more active if the placenta in complicated pregnancy is carrying male fetus than when it is carrying a female fetus.
Further research based on the current study may offer the answer to the mysterious link between males and risk of mental illness in the future.
"The surprising results of this study make the placenta the centerpiece of a new realm of biological investigation related to how genes and the environment interact to alter the trajectory of human brain development," Weinberger added.