Serotonin and anger

[Hans de Vries]

CharonY mentioned relationship between serotonin and anger/aggression.

How strong is the relationship? Is the effect size huge? Is is a clear case that levels of anger and agression drop with increased levels of serotonin?

[Phi for All]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3718863/

Quote

The evidence for the serotonin deficiency hypothesis of human aggression lacks corroboration. Contradictory findings, unreliable measurement, and a high degree of complexity leave our overall finding of a small inverse correlation between serotonin and human aggression open to multiple, equally plausible interpretations. While the overall relation between serotonin and human aggression is currently unclear, the four recommendations below hold promise in advancing this important area of research and paving the way for future clarity.

CharonY also mentioned that some psychologist is trying to play biologist and claim correlation between serotonin level effects in lobsters with their effect on humans.

[CharonY]

There are some newer studies out there, but fundamentally the strongest link is seen in cases of severe deficiencies where impulse aggression seems to be elevated. Outside of extremes the evidence points to perhaps a slight inverse relationship, but it is certainly not a simple quantitative correlation.

That, btw. is a common finding in human subjects. For complex traits there is rarely a simple quantitative relationship between a given trait/behaviour/psychological state and a given marker. In some cases changes are more indicative (e.g. increase or decrease of certain hormones as opposed to their absolute values) but almost always the situation is complex. It is likely also for many animals, but we lack the ability to define nuances that we can do with humans, as we can simply talk to folks.

[Hans de Vries]

On 11/18/2021 at 7:53 PM, CharonY said:

There are some newer studies out there, but fundamentally the strongest link is seen in cases of severe deficiencies where impulse aggression seems to be elevated. Outside of extremes the evidence points to perhaps a slight inverse relationship, but it is certainly not a simple quantitative correlation.

That, btw. is a common finding in human subjects. For complex traits there is rarely a simple quantitative relationship between a given trait/behaviour/psychological state and a given marker. In some cases changes are more indicative (e.g. increase or decrease of certain hormones as opposed to their absolute values) but almost always the situation is complex. It is likely also for many animals, but we lack the ability to define nuances that we can do with humans, as we can simply talk to folks.

Are there alternate neurobiological hypotheses of anger?

[CharonY]

On 11/26/2021 at 3:44 AM, Hans de Vries said:

Are there alternate neurobiological hypotheses of anger?

There are a lot of papers dealing with the neurophysiology of aggression, including fMRI studies. Especially in humans the question is whether the tests used to assess aggression are sufficiently accurate (so that the measured neuronal correlates are actually related to aggression and not e.g. just stress or other associated states). But this is way outside my expertise and at least from the little I have seen there is (I think) no consensus model as of yet.