Elucidation needed
Results showed that, of the 4,676 offspring of mothers with PID, 17.1% had a psychiatric disorder versus 12.7% of offspring of mothers without PIDs. This translated “into a 17% increased risk for offspring of mothers with PIDs in the fully adjusted model,” the investigators reported.
The risk was even higher for offspring of mothers who had not only PIDs but also one of six of the individual psychiatric disorders, with incident rate ratios ranging from 1.15 to 1.71.
“In fully adjusted models, offspring of mothers with PIDs had an increased risk of any psychiatric disorder, while no such risks were observed in offspring of fathers with PIDs” (IRR, 1.17 vs. 1.03; P < .001), the researchers reported.
A higher risk for suicidal behavior was also observed among offspring of mothers with PIDS, in contrast to those of fathers with PIDs (IRR, 1.2 vs. 1.1; P = .01).
The greatest risk for any psychiatric disorder, as well as suicidal behavior, was found in offspring of mothers who had both PIDs and autoimmune diseases (IRRs, 1.24 and 1.44, respectively).
“The results could be seen as substantiating the hypothesis that immune disruption may be important in the pathophysiology of psychiatric disorders and suicidal behavior,” Dr. Isung said.
“Furthermore, the fact that only offspring of mothers and not offspring of fathers with PIDs had this association would align with our hypothesis that MIA is of importance,” he added.
However, he noted that “the specific mechanisms are most likely multifactorial and remain to be elucidated.”
Important piece of the puzzle?
In a comment, Michael Eriksen Benros, MD, PhD, professor of immunopsychiatry, department of immunology and microbiology, health, and medical sciences, University of Copenhagen, said this was a “high-quality study” that used a “rich data source.”
Dr. Benros, who is also head of research (biological and precision psychiatry) at the Copenhagen Research Centre for Mental Health, Copenhagen University Hospital, was not involved with the current study.
He noted that prior studies, including some conducted by his own group, have shown that maternal infections overall did not seem to be “specifically linked to mental disorders in the offspring.”
However, “specific maternal infections or specific brain-reactive antibodies during the pregnancy period have been shown to be associated with neurodevelopmental outcomes among the children,” such as intellectual disability, he said.
Regarding direct clinical implications of the study, “it is important to note that the increased risk of psychiatric disorders and suicidality in the offspring of mothers with PID were small,” Dr. Benros said.
“However, it adds an important part to the scientific puzzle regarding the role of maternal immune activation during pregnancy and the risk of mental disorders,” he added.
The study was funded by the Söderström König Foundation and the Fredrik and Ingrid Thuring Foundation. Neither Dr. Isung nor Dr. Benros reported no relevant financial relationships.
A version of this article originally appeared on Medscape.com.