March 13, 2007
Serotonin Receptor Makes Women Angry?

Ladies, next time you get angry at someone you can blame it on your DNA - unless of course you want to blame it on the object of your anger.

BUDAPEST, HUNGARY, March 9 Ever wonder why some women seem to be more ill-tempered than others? University of Pittsburgh researchers have found that behaviors such as anger, hostility and aggression may be genetic, rooted in variations in a serotonin receptor gene. Indrani Halder, Ph.D., of the Cardiovascular Behavioral Medicine Program at the University of Pittsburgh, will present the findings today at the American Psychosomatic Society's Annual Meeting, held in Budapest, Hungary.

Previous studies have associated the hormone serotonin with anger and aggression in both humans and animals and have shown that increased serotonin activity is related to a decrease in angry and aggressive behaviors. In the study being presented today, researchers sought to determine if this relationship was genetically determined. The study is the first to look at the relationship between variations in the serotonin receptor 2C gene and anger and hostility.

Completed at the University of Pittsburgh's Behavioral Physiology Laboratory, the study looked at 550 unrelated women of European descent. In order to find normal variations in genes and behavior, the women were not prescreened for behavioral type. Researchers found that those who had one or both of two alterations in the promoter region of the serotonin receptor 2C gene were more likely to score lower on two common tests for anger, hostility and aggression.

But not so fast. Robert Plomin, who has spent years trying to find gene alleles that produce differences in intelligence, thinks the search for genes that influence cognitive qualities is so hard that these latest results are unlikely to be correct.

"Individual differences in aggression and anger are influenced by genes -- as are all personality traits -- but progress in identifying the genes has been slower than researchers expected," added Prof Robert Plomin, deputy director of the Social, Genetic and Development Psychiatry Centre, London. "Thousands of reports of this gene or that gene being related to complex traits or common disorders in the end fail to replicate, not just for behaviour but also for medical problems such as dementia and heart disease."

I am very keen to find out which genetic variations create differences in personality, intelligence, and other aspects of cognitive function. But since Plomin and other scientists think each mental trait is controlled by many gene alleles and each variation contributes only a small amount to the total result. So identifying a genetic influence above the background noise of other genetic variations and environmental influences is very difficult.

The solution to this problem? Huge decreases in the cost of DNA testing. Gene chips that test hundreds of thousands of single letter DNA differences at once have already hit the market quite recently. We need gene testing cheap enough that thousands or tens of thousands of genetic variations can be checked in each person in a study. We also need costs so low that thousands or even tens of thousands of people can get checked at once. Then scientists will be able to control for enough genetic variations at once to identify those that are really influencing cognitive function.

We are waiting for advances in gene chip and microfluidics biotechnology so that scientific questions about human genomes become easy to answer. Most of what we are going to learn about human genetic differences is going to be figured out in a short period of time after decades of attempts to answer those questions. The instrumentation advances are more important than any one or ten of the scientific discoveries that will come from them.

Share |      Randall Parker, 2007 March 13 12:17 AM  Brain Genetics

Curious said at March 13, 2007 3:52 PM:

I wonder... for a woman suffering from this, what supplement/nootropic might help mellow/aleviate the symptoms?

birch barlow said at March 14, 2007 9:07 PM:

I'm surprised that researches have not been able to identify the genes related to endorphins, endopsychosins, endogenous stimulants, endocanniboids, endogenous nicotinic receptor agonists, etc. since the endogenous compounds themselves *have* been identified. I can't imagine that gene variants in the genes responsible for making these compounds would not have a profound impact on personality, as these compounds are essentially natural narcotics. It's quite obvious that taking exogenous analogues to these substances causes profound changes in emotion.

This may sound a little conspiracy-theory sounding, but I wonder if such studies have been supressed. The idea of locking up someone for taking a compound that simply brings them up from say, the 5th percentile in activity of a given system (endopsychosin, endogenous stimulant, endocanniboid etc), to the 95th percentile would seem preposterous in such terms--or maybe we should just find people with naturally high concentrations of these compounds in their brains, and lock them up for winning the genetic lottery. Seriously, groups like the Partership for a Drug Free America are fascist groups that are doing little more than promote genetic discrimination (of course, others who advocate genetic discrimination, like ethnic studies profs, are being paid tens of thousands of dollars a year to advocate a different kind of genetic discrimination--so what can I expect?)

birch barlow said at March 14, 2007 9:35 PM:

The idea of locking up someone for taking a compound that simply brings them up from say, the 5th percentile in activity of a given system (endopsychosin, endogenous stimulant, endocanniboid etc), to the 95th percentile would seem preposterous in such terms

To be fair, many narcotic* users are using these substances to the point that whatever system(s) their substance(s) of choice are being stimulated far outside the normal range--perhaps even to 5, 10, or more standard deviations above the natural mean of the activity of these systems. A substantial number (though probably significantly less than 50%) of (ab)users of a given substance have natural levels of activity in the affected receptor system above the human/mammal/vertebrate median to begin with.

I think many of the traditional markers of "drug abuse" (especially the dopier--pardon the pun--ones like use for psychological effect** illegality, use contrary to labeling, and other such legalistic and simple-mindednonsense) should be replaced by biochemical ones--e.g., is the user consistently taking substances to where their narcotic receptor systems are well above the normal range.

*I am speaking of "narcotic" in the broad sense of a powerful euphoria-inducing drug, rather than the narrow sense of opiates

**I'd like to bring up the "duh" theory of substance use here--whether we are talking about alcohol, nicotine, pot, certain OTC and prescription meds, traditional street drugs, or whatever. People use mind-altering substances to alter their mind in a way that feels favorable to them--DUH!! For some strange reason many people see this is shocking--for example, Bill O'Reilly essentially said alcohol is "OK" because most people don't use it for psychoactive moronic and moralistic can one get?...and O'Reilly's statement is tame compared to the fascist nonsense that would come out of much of Middle America.

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