A problematic study of oxytocin receptor gene methylation, childhood abuse, and psychiatric symptoms

This 2016 Georgia human study found:

“A role for OXTR [oxytocin receptor gene] in understanding the influence of early environments on adult psychiatric symptoms.

Data on 18 OXTR CpG sites, 44 single nucleotide polymorphisms, childhood abuse, and adult depression and anxiety symptoms were assessed in 393 African American adults. The Childhood Trauma Questionnaire (CTQ), a retrospective self-report inventory, was used to assess physical, sexual, and emotional abuse during childhood.

While OXTR CpG methylation did not serve as a mediator to psychiatric symptoms, we did find that it served as a moderator for abuse and psychiatric symptoms.”

From the Limitations section:

  1. “Additional insight will likely be gained by including a more detailed assessment of abuse timing and type on the development of biological changes and adverse outcomes.
  2. The degree to which methylation remains fixed following sensitive developmental time periods, or continues to change in response to the environment, is still a topic of debate and is not fully known.
  3. Comparability between previous findings and our study is limited given different areas covered.
  4. Our study was limited to utilizing peripheral tissue [blood]. OXTR methylation should ideally be assessed in the tissues that are known to express OXTR and directly involved in psychiatric symptoms. The degree to which methylation of peripheral tissues can be used to study methylation changes in response to the environment or in association with behavioral outcomes is currently a topic of debate.
  5. Our study did not evaluate gene expression and thus cannot explore the role of study CpG sites on regulation and expression.”

Addressing the study’s limitations:

  1. Early-life epigenetic regulation of the oxytocin receptor gene demonstrated – with no hint of abuse – how sensitive an infant’s experience-dependent oxytocin receptor gene DNA methylation was to maternal care. Treating prenatal stress-related disorders with an oxytocin receptor agonist provided evidence for prenatal oxytocin receptor gene epigenetic changes.
  2. No human’s answers to the CTQ, Adverse Childhood Experiences, or other questionnaires will ever be accurate self-reports of their prenatal, infancy, and early childhood experiences. These early development periods were likely when the majority of the subjects’ oxytocin receptor gene DNA methylation took place. The CTQ self-reports were – at best – evidence of experiences at later times and places, distinct from earlier experience-dependent epigenetic changes.
  3. As one example of incomparability, the 2009 Genomic and epigenetic evidence for oxytocin receptor deficiency in autism was cited in the Introduction section and again in the Limitations section item 4. Since that study was sufficiently relevant to be used as a reference twice, the researchers needed to provide a map between its findings and the current study.
  4. Early-life epigenetic regulation of the oxytocin receptor gene answered the question of whether or not an individual’s blood could be used to make inferences about their brain oxytocin receptor gene DNA methylation. The evidence said: NO, it couldn’t.
  5. It’s assumed that oxytocin receptor gene DNA methylation directly impacted gene expression such that increased levels of methylation were associated with decreased gene transcription. The study assumed but didn’t provide evidence that higher levels of methylation indicated decreased ability to use available oxytocin due to decreased receptor expression. The study also had no control group.

To summarize the study’s limitations:

  1. The study zeroed in on childhood abuse, and disregarded evidence for more relevant factors determining an individual’s experience-dependent oxytocin receptor gene DNA methylation. That smelled like an agenda.
  2. The study used CTQ answers as determinants, although what happened during the subjects’ earliest life was likely when the majority of epigenetic changes to the oxytocin receptor gene took place. If links existed between the subjects’ early-life DNA methylation and later-life conditions, they weren’t evidenced by CTQ answers about later life that couldn’t self-report relevant experiences from conception through age three that may have caused DNA methylation.
  3. There was no attempt to make findings comparable with cited studies. That practice and the lack of a control group reminded me of Problematic research with telomere length.
  4. The researchers tortured numbers until they confessed “that CpG methylation may interact with abuse to predict psychiatric symptoms.” But there was no direct evidence that each subject’s blood oxytocin gene receptor DNA methylation interacted as such! Did the “may interact” phrase make the unevidenced inferences more plausible, or permit contrary evidence to be disregarded?
  5. See Testing the null hypothesis of oxytocin’s effects in humans for examples of what happens when researchers compound assumptions and unevidenced inferences.

The study’s institution, Emory University, and one of the study’s authors also conducted Conclusions without evidence regarding emotional memories. That 2015 study similarly disregarded relevant evidence from other research, and made statements that weren’t supported by that study’s evidence.

The current study used “a topic of debate” and other disclaimers to provide cover for unconvincing methods and analyses in pursuit of..what? What overriding goals were achieved? Who did the study really help?

http://onlinelibrary.wiley.com/enhanced/doi/10.1111/cdev.12493/ “Oxytocin Receptor Genetic and Epigenetic Variations: Association With Child Abuse and Adult Psychiatric Symptoms”


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Early-life epigenetic regulation of the oxytocin receptor gene

This 2015 US/Canadian rodent study investigated the effects of natural variation in maternal care:

“The effects of early life rearing experience via natural variation in maternal licking and grooming during the first week of life on behavior, physiology, gene expression, and epigenetic regulation of Oxtr [oxytocin receptor gene] across blood and brain tissues (mononucleocytes, hippocampus, striatum, and hypothalamus).

Rats reared by high licking-grooming (HL) and low licking-grooming (LL) rat dams exhibited differences across study outcomes:

  • LL offspring were more active in behavioral arenas,
  • Exhibited lower body mass in adulthood, and
  • Showed reduced corticosterone responsivity to a stressor.

Oxtr DNA methylation was significantly lower at multiple CpGs in the blood of LL versus HL males, but no differences were found in the brain. Across groups, Oxtr transcript levels in the hypothalamus were associated with reduced corticosterone secretion in response to stress, congruent with the role of oxytocin signaling in this region.

Methylation of specific CpGs at a high or low level was consistent across tissues, especially within the brain. However, individual variation in DNA methylation relative to these global patterns was not consistent across tissues.

These results suggest that:

  • Blood Oxtr DNA methylation may reflect early experience of maternal care, and
  • Oxtr methylation across tissues is highly concordant for specific CpGs, but
  • Inferences across tissues are not supported for individual variation in Oxtr methylation.

nonsignificance

Individual DNA methylation values were not correlated across brain tissues, despite tissue concordance at the group level.

For each CpG, we computed the Pearson correlation coefficient r between methylation values for matched samples in pairs of brain regions (bars). Dark and light shaded regions represent 95% and 99% thresholds, respectively, of distributions of possible correlation coefficients determined from 10,000 permutations of the measured values among the individuals. These distributions represent the null hypothesis that an individual DNA methylation value in one brain region does not help to predict the value in another region in the same animal.

(A) Correlations based on pyrosequencing data for matched samples passing validation in both hippocampus (HC) and hypothalamus (Hypo). Correlations for individuals at each CpG were either weak (.2 < r < .3) or absent (r < .2), and none were significant, even prior to correction for multiple comparisons.

(B) Correlations for matched samples passing validation in both hippocampus and striatum (Str). Two correlations (CpG 1 and 11) were individually significant prior to but not following correction, and this result could be expected by chance.

Correlations between hippocampus and blood (described in the text) yielded similar results, and no particular CpG yielded consistently high correlation across multiple tissues.”


The study focused on whether or not an individual’s experience-dependent oxytocin receptor gene DNA methylation in one of the four studied tissues could be used to infer a significant effect in the three other tissues. The main finding was NO, it couldn’t!

The researchers’ other findings may have been strengthened had they also examined causes for the observed effects. The “natural variation in maternal licking and grooming” developed from somewhere, didn’t it?

The subjects’ mothers were presumably available for the same tests as the subjects, but nothing was done with them. Investigating at least one earlier generation may have enabled etiologic associations of “the effects of early life rearing experience” and “individual variation in DNA methylation.”

https://www.sciencedirect.com/science/article/abs/pii/S0018506X1500118X “Natural variation in maternal care and cross-tissue patterns of oxytocin receptor gene methylation in rats” (not freely available)

Does vasopressin increase mutually beneficial cooperation?

This 2016 German human study found:

“Intranasal administration of arginine vasopressin (AVP), a hormone that regulates mammalian social behaviors such as monogamy and aggression, increases humans’ tendency to engage in mutually beneficial cooperation.

AVP increases humans’ willingness to cooperate. That increase is not due to an increase in the general willingness to bear risks or to altruistically help others.”


One limitation of the study was that the subjects were all males, ages 19-32. The study’s title was “human risky cooperative behavior” while omitting subjects representing the majority of humanity.

Although the researchers claimed brain effects from vasopressin administration, they didn’t provide direct evidence for the internasally administered vasopressin in the subjects’ brains. A similar point was made about studies of vasopressin’s companion neuropeptide, oxytocin, in Testing the null hypothesis of oxytocin’s effects in humans.

A third limitation was that although the researchers correlated brain activity with social behaviors, they didn’t carry out all of the tests necessary to demonstrate the claimed “novel causal evidence for a biological factor underlying cooperation.” Per Confusion may be misinterpreted as altruism and prosocial behavior, the researchers additionally needed to:

“When attempting to measure social behaviors, it is not sufficient to merely record decisions with behavioral consequences and then infer social preferences. One also needs to manipulate these consequences to test whether this affects the behavior.”

http://www.pnas.org/content/113/8/2051.full “Vasopressin increases human risky cooperative behavior”

Treating prenatal stress-related disorders with an oxytocin receptor agonist

This 2015 French/Italian rodent study found:

“Chronic systemic treatment with carbetocin [unavailable in the US] in PRS [prenatally restraint stressed] rats corrected:

  • the defect in glutamate release,
  • anxiety– and depressive-like behavior,

and abnormalities:

  • in social behavior,
  • in the HPA response to stress, and
  • in the expression of stress-related genes in the hippocampus and amygdala.

These findings disclose a novel function of oxytocin receptors in the hippocampus, and encourage the use of oxytocin receptor agonists in the treatment of stress-related psychiatric disorders in adult life.”

carbetocin

The adult male subjects were:

“PRS rats..the offspring of dams exposed to repeated episodes of restraint stress during pregnancy.

These rats display anxiety- and depressive-like behaviors and show an excessive glucocorticoid response to acute stress, which is indicative of a dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis caused by an impaired hippocampal glucocorticoid negative feedback.

PRS rats show a selective reduction in glutamate release in the ventral hippocampus.”

The researchers cited several other studies they have performed with the PRS phenotype. In the current study:

“Carbetocin treatment had no effect on these behavioral and neuroendocrine parameters in prenatally unstressed (control) rats, with the exception of a reduced expression of the oxytocin receptor gene in the amygdala.

Carbetocin displayed a robust therapeutic activity in PRS rats, but had no effect in unstressed rats, therefore discriminating between physiological and pathological conditions.”


The PRS phenotype showed the ease with which a child can be epigenetically changed – even before they’re born – to be less capable over their entire life. Just stress the pregnant mother-to-be.

https://www.sciencedirect.com/science/article/abs/pii/S0306453015002395 “Activation of presynaptic oxytocin receptors enhances glutamate release in the ventral hippocampus of prenatally restraint stressed rats” (not freely available) Thanks to coauthor Dr. Eleonora Gatta for providing the full study.

Testing the null hypothesis of oxytocin’s effects in humans

“There are so many reports of relationships between oxytocin and social behaviors. It is impossible that not a single one of these effects is real.

Isn’t it?

When running a battery of three tasks for every subject who underwent oxytocin treatment..finding false effects becomes almost guaranteed – over 90%.”

http://theneuroeconomist.com/2016/01/the-self-justification-molecule-how-have-we-accumulated-a-vast-behavioral-oxytocin-literature-for-over-a-decade/ “The self-justification molecule: how have we accumulated a vast behavioral oxytocin literature for over a decade”


From one of the references, Why Most Published Research Findings Are False:

“For many current scientific fields, claimed research findings may often be simply accurate measures of the prevailing bias.”


Also see the researcher’s response on their blog post Does oxytocin increase trust in humans? Frequently asked questions:

“Scientists publish only positive findings and not negative ones, and I cannot think of a single study in the vast human oxytocin literature that was replicated by an independent research group.”

Beliefs about medical treatments affected perceived stress

This 2015 New Zealand human study found:

“Placebo effects can be translated to a real-life setting in the short-term reduction of stress, anxiety and symptoms of depression in a non-patient population.

In treating psychological distress, placebos may be useful addition to the treatment repertoire.

The researchers provided a self-administered 3-day course of fake “anti-stress treatment spray” and told the participants the spray was either “oxytocin” or “serotonin” with these results:

“Both the ‘serotonin’ and ‘oxytocin’ treatment sprays were effective in reducing symptoms of depression; however, only those in the ‘oxytocin’ group reported less stress and anxiety as compared with controls. Overall, the ‘oxytocin’ was perceived as more effective.”


Will this study of non-patients be used to try to justify manipulating patients’ perceptions of their stress, anxiety, and depression?

http://anp.sagepub.com/content/early/2015/12/16/0004867415621390 “A take-home placebo treatment can reduce stress, anxiety and symptoms of depression in a non-patient population”

Leaky gates, anxiety, and grocery store trips without buying list items

An interview with Jeff Link, the editor of Dr. Arthur Janov’s 2011 book “Life Before Birth: The Hidden Script that Rules Our Lives” with Ken Rose:

Even further confirmation for some of the views of Janov, that maybe weren’t widely accepted for a time, it’s new research now being done into memory and what a lot of scientist are seeing, a lot of different studies is that memory reactivates the same neuroimpulses that were initially firing off when the event happened.

So a traumatic event when you remember it, the act of remembering it is actually creating a neuromirror of what went on initially.

In a lot of ways that is what Primal Therapy is attempting to do; is to go back to that place and reconnect, or as it’s sometimes referred to, reconsolidate the brain state so that real healing can take place.

Transcript (part 4 of 6): http://cigognenews.blogspot.com/2015/09/ken-rose-on-life-before-birth-part-46.html

MP3: http://www.pantedmonkey.org/podcastgen/download.php?filename=2011-12-15_1300_what_now_jeff_link.mp3