They literally are proposing that psychological stress may mutate the mitochondrial DNA:
The mtDNA does not have loose ends and thus does not contain telomeres, the DNA-protein complexes that cap the end of chromosomes in the nucleus (
33). The mtDNA also lacks introns and is more susceptible to damage in comparison to the nuclear genome (
34), which may explain its greater vulnerability to damage with aging, and possibly with chronic stress.
No humans involved in these studies, which also makes their relevance far less likely:
There were no human study with induced psychosocial stress monitoring mitochondrial function, so all studies included are in animal models.
Changes in DNA were not outcomes in any studies:
Only studies directly measuring at least one aspect of mitochondrial function (e.g., respiration, respiratory chain enzymatic activity, and ROS production), or electron microscopy studies quantifying changes in mitochondrial morphology or structure, were included
Most of the stressors included a substantial physical factor:
The stressors most frequently used was chronic restraint stress (e.g., 21 consecutive days of physical restraint, 2 hours per day; 38%), followed by chronic unpredictable stress (e.g., 40 consecutive days with alternating novel environmental exposures on each day; 33%) and acute restraint stress (e.g., a single bout of physical restraint lasting 30–120 minutes; 21%).
How the mitochondria were assessed:
In 46% of studies, mitochondrial function and integrity were most often measured via respiratory chain enzymatic activity, which can be assessed on frozen tissues (
73). Other outcomes included oxygen consumption (33%), quantitative electron microscopy (29%), membrane potential (13%), ATP synthesis (13%), and ROS production (8%). Mitochondrial DNA copy number, which is not a measure of mitochondrial function, was measured in 9% of studies.
Table 1 lists the results of various studies, and it's pretty suggestive of false positive results - sometimes there's increased respiration in response to stress, sometimes it's decreased. Sometimes mitochondrial size increases, sometimes it decreases, and sometimes it stays the same. Sometimes respiratory chain activity increases, sometimes it decreases. Sometimes the results on the some measurement in the same study are only different based on subgrouping, which is usually the result of post-hoc cherry picking.
Table 2 lists associations between various mitochondrial-related measurements and mood disorders or history of abuse, in 6 studies involving humans. Results are a bit mixed again, and the more obvious explanation is that mitochondrial dysfunction causes the symptoms of mood disorders in those patients, combined with retrospective recall bias regarding childhood trauma (who also had increased inflammation). I find it amusing that they have flipped the usual cause and effect (genes cause disease) to call that "reverse causation" in ceding it might be a possibility:
Whether psychological symptoms (e.g., anhedonia and sadness in major depression) cause changes in mtDNA, or whether changes in mtDNA reflect an underlying pathophysiological state that contributes to psychological symptoms (i.e., reverse causation), remains to be determined.
They refer to autism as a "psychopathology," which seems a good indication that they have been living in a cave and will continue to do so until it collapses on them:
Another study targeted caregiver women who care for a child with autism spectrum disorder, which is a psychopathology that fosters elevated levels of psychological distress in the caregivers given its detrimental impact in various life domains of the child (e.g., persistent deficits in social communication, stereotyped or repetitive behaviors and interests).
My overall impression is that not only can we use the powers of our minds to grow hand-claws, we can also alter our genomes through sheer force of will and pass on those hand-claws to the next generation
I'd be shocked that this study ever got published, but it's a psychosomatic journal and scientific standards are likely completely irrelevant
