Can you detect psychopathy in snot?

 

M.E. Thomas and Dr. Phil

How about an objective test to determine the validity of the author’s claims?

The surreal conversation of daytime TV psychology:

Author: “I’m a sociopath”

Dr. Phil: “Are you scamming me?”

Recently, a self-proclaimed “sociopath” wrote a book and went on book tour, only to be received with much skepticism. This brings into high relief, we think, the need for objective indicia of a DSM-based clinical diagnosis. Or maybe new diagnostic categories altogether.

And so we follow reports of mental health biomarkers with interest.

The sense of smell is sometimes the first to go when the brain goes south, so it is interesting that olfactory biomarkers for schizophrenia are reported.  We wonder if this related to a previous report that psychopaths have an impaired sense of smell (blogged here). Although the current test involves removing actual nerve cells in the nose (under anesthesia), how far away can a snot test really be?

The study included 25 schizophrenics hospitalized at Johns Hopkins University Medical Center in Baltimore, which was a partner in the study, plus 25 healthy subjects. The nerve cells were swabbed from the subjects’ noses under local anesthesia. The researchers then screened the 2,000 genetic controls contained within these cells, using a method called high-output genetic mapping.

Haaretz, full cite below.

Wouldn’t daytime TV be better with an on-air snot test to validate sociopathy claims? 

Be that as it may.

We also wonder if these little bitty pieces of DNAs/RNAs are a reaction against some kind of environmental stress, sort of like the immune system. Could there be a vaccine against psychopathology?

The biomarkers in the schizophrenia reports are little bitty pieces of RNAs that swim around wreaking havoc on genes. Normally, genes are just trying to do their jobs, turning on, turning off, turning up the volume, turning down the volume, the regular stuff they do, and then microRNAs come along:

. . .microRNAs (miRNAs) are small non-coding RNAs with the ability to silence the expression of multiple target genes by binding to specific sequences of mRNAs. A single miRNA can impact hundreds to thousands of targets and can affect pathways controlling a large variety of processes, from normal development to oncogenesis. Pairing is primarily based on sequence complementarity of a “seed” sequence within the miRNA to a binding site of the mRNA, generally in the 3′ UTR of the mRNA being suppressed . The mechanisms by which miRNAs suppress gene expression are still not well elucidated; however mRNA destabilization and translational repression have been demonstrated as dominant methods of repressing subsequent protein expression .. . .

Wright et al, PMC3636510, cited below, citations omitted.

Micro RNAs are in the parade of outlaw genetic bits that run around either messing things up or fixing things depending on your perspective. They are sort of the anarchists of nucleic acids. Our view is that they spring into action upon some environmental emergency — like, a toxin (in utero alcohol? drugs?) or excess production of a natural compound (stress hormones during war, for instance), and readjust the genetic regulation to cope with extraordinary circumstances.* Transposable elements, endogenous retroviruses (ERVs), and we suspect all sorts of other bits and pieces yet to be found out are traipsing around screwing with our gene regulation, with no unifying principle that we can ascertain.

Discovery of micro RNAs is relatively new because, like other bits of DNA or RNA that jump around, these aren’t strictly Mendelian, and the conventional wisdom was that animals don’t have a whole lot of extra-chromosomal regulation. Your loyal bloggist, for instance, had the impression that jumping genetic elements were only common in plants or bacteria or viruses or other things of limited mobility and cognition.We were taught, or maybe we just imagined, that the AC/DS system of jumping genes that makes the politically awkward named Indian corn so colorful was because corn can’t just run away from their environmental discomfort. 

But then came reports of environmental-stress-induced epigenetic changes in utero, like war-induced stress (blogged here, back in 2008), and alcoholism ( here, endogenous retroviruses in alcoholic brains). 

One of the interesting things about the schizophrenia work is that the axonal guidance pathway is affected. That means micro RNAs screw with connectivity. (See our “white matter” category, which should really be renamed “connectivity”). Hear voices? Paranoid? Make no mistake, this is directly related to how nerve cells correctly, or incorrectly, connect.  So perhaps the axons are led astray by rogue micro RNAs, resulting in the schizophrenic-thought patterns seen by clinicians.

Psychopaths have less global, and more local neural disconnects —  the empathy pathway is unplugged (blogged ad nauseum, see here, e.g.).  Although, the psychopaths in our lives seem to have psychotic breaks now and again (which are extremely scary to be around, especially if the target of the paranoia is you.)  So perhaps there are the same micro RNA biomarkets relating to axonal guidance disruption, but on a more localized scale. We’d like to see some micro RNA biomarker tests for psychopaths.

 

Some papers:

Jin XF, Wu N, Wang L, Li J. Circulating MicroRNAs: A Novel Class of Potential Biomarkers for Diagnosing and Prognosing Central Nervous System Diseases. Cell Mol Neurobiol. 2013 Apr 30. [Epub ahead of print] PubMed PMID: 23633081.

Mor E, Kano S, Colantuoni C, Sawa A, Navon R, Shomron N. MicroRNA-382 expression is elevated in the olfactory neuroepithelium of schizophrenia patients. Neurobiol Dis. 2013 Jul;55:1-10. doi: 10.1016/j.nbd.2013.03.011. Epub 2013 Mar 29. PubMed PMID: 23542694.

See also:

Wright C, Turner JA, Calhoun VD, Perrone-Bizzozero N. Potential Impact of miR-137 and Its Targets in Schizophrenia. Front Genet. 2013 Apr 26;4:58. doi: 10.3389/fgene.2013.00058. Print 2013. PubMed PMID: 23637704; PubMed Central PMCID: PMC3636510.

Dan Even, “Israeli researchers find new way of detecting schizophrenia,” Haaretz, 04.23.13

 

*Yes, we know, we tend to anthropomorphize to the point of oversimplification. We have no regrets.