The fifth and final paper of Transgenerational epigenetic inheritance week was a 2017 German/Italian meta-analysis of psychiatric treatments involving human children:
“The transgenerational transmission of mental disorders is one of the most significant causes of psychiatric morbidity. Several risk factors for children of parents with mental illness (COPMI) have been identified in numerous studies and meta-analyses.
There is a dearth of high quality studies that effectively reduce the high risk of COPMI for the development of mental disorders.”
I found the study by searching a medical database on the “transgenerational” term. The authors fell into the trap of misusing “transgenerational” instead of “intergenerational” to describe individuals in different generations.
Per the definitions in A review of epigenetic transgenerational inheritance of reproductive disease and Transgenerational effects of early environmental insults on aging and disease, for the term “transgenerational transmission” to apply, the researchers needed to provide evidence in at least the next 2 male and/or 3 female generations of:
“Altered epigenetic information between generations in the absence of continued environmental exposure.”
The meta-analysis didn’t provide evidence for “transgenerational transmission of mental disorders.”
Several aspects of the meta-analysis stood out:
- Infancy was the earliest period of included studies, and studies of treatments before the children were born were excluded;
- Parents had to be diagnosed with a mental illness for the study to be included;
- Studies with children diagnosed with a mental illness were excluded; and
- Studies comparing more than one type of intervention were excluded.
Fifty worldwide studies from 1983 through 2014 were selected for the meta-analysis.
Per item 1 above, if a researcher doesn’t look for something, it’s doubtful that they will find it. As shown in the preceding papers of Transgenerational epigenetic inheritance week, the preconception and prenatal periods are when the largest epigenetic effects on an individual are found. There are fewer opportunities for effective “preventive interventions” in later life compared with these early periods.
Science provides testable explanations and predictions. The overall goal of animal studies is to help humans.
Animal studies thus provide explanations and predictions for the consequences of environmental insults to the human fetus – predictable disrupted neurodevelopment with subsequent deviated behaviors and other lifelong damaging effects in the F1 children. The first four papers I curated during Transgenerational epigenetic inheritance week provided samples of which of these and/or other harmful effects may be predictably found in F2 grandchildren, F3 great-grandchildren, and future human generations.
When will human transgenerational epigenetic inheritance be taken seriously? Is the root problem that human societies don’t give humans in the fetal stage of life a constituency, or protection against mistreatment, or even protection against being arbitrarily killed?
The default answer to the meta-analysis title “Do preventive interventions for children of mentally ill parents work?” is No. As for the “dearth of high quality studies” complaint: when treatments aren’t effective, is the solution to do more of them?
The researchers provided an example of the widespread belief that current treatments for “psychiatric morbidity” are on the right path, and that the usual treatments – only done more rigorously – will eventually provide unquestionable evidence that they are effective.
This belief is already hundreds of years old. How much longer will this unevidenced belief survive?
http://journals.lww.com/co-psychiatry/Abstract/2017/07000/Do_preventive_interventions_for_children_of.9.aspx “Do preventive interventions for children of mentally ill parents work? Results of a systematic review and meta-analysis” (not freely available)