Why Do We Get Angry? – New Research

Why is it that some people get angry at the littlest thing while others have the patience of Job?

New research from the University of Cambridge finds that low levels of serotonin in your brain have a major impact upon how you react to that jerk who cut you off in traffic this morning.

Building upon previous serotonin/aggression research, this study is the first to show how serotonin helps regulate behavior in your brain as well as why some people are more prone to aggression.

The Science

In this study, healthy volunteers’ serotonin levels were altered by manipulating their diet.

  • On the serotonin depletion day, they were given a mixture of amino acids that lacked tryptophan, the building block for serotonin.
  • On the placebo day, they were given the same mixture but with a normal amount of tryptophan.

The researchers then scanned the volunteers’ brains using functional magnetic resonance imaging (fMRI) as they viewed faces with angry, sad, and neutral expressions. Using the fMRI, they were able to measure how different brain regions reacted and communicated with one another when the volunteers viewed angry faces, as opposed to sad or neutral faces.

The research revealed that low brain serotonin made communications between specific brain regions of the emotional limbic system of the brain (a structure called the amygdala) and the frontal lobes weaker compared to those present under normal levels of serotonin.

The findings suggest that when serotonin levels are low, it may be more difficult for the prefrontal cortex to control emotional responses to anger that are generated within the amygdala.

Using a personality questionnaire, they also determined which individuals have a natural tendency to behave aggressively.

In these individuals, the communications between the amygdala and the prefrontal cortex was even weaker following serotonin depletion. ‘Weak’ communications means that it is more difficult for the prefrontal cortex to control the feelings of anger that are generated within the amygdala when the levels of serotonin are low.

As a result, those individuals who might be predisposed to aggression were the most sensitive to changes in serotonin depletion.

What Does This Mean to You?

It means that if you don’t want to live your life being Mr. or Ms. Grumpy, you may want to take steps to avoid low serotonin.

These steps can include:




  1. Interesting. However, having too much serotonin is just as bad. Being too comfortable and content and NOT having reactions to things pretty much ensures that you’re NOT going to be motivated to do anything to change your habits, confront people about things, or improve your situation. Our instinctive reactions are there for a reason. The better we know ourselves, the more equipped we are to handle situations and bring about positive outcomes. I’ve taken SSRI’s already and they made me completely content, apathetic, and useless…destroyed my motivation. So maybe increasing serotonin isn’t the best solution for everyone – knowing yourself and exercising a bit of self-restraint is a much more balanced approach.

  2. First of all thanks for this great article I really like it. I’m one of the less angry persons, but I know some people who get angry at the smallest things. So I will send this article to them maybe it will help them.

  3. Is there any science to determine how much more susceptible a gender is to rages due to serotonin depletion? My wife and daughters are often out of control.

  4. I believe fight or flight is still in operation. Its just that some people have hair-triggers that exacerbate situations. A person who will allow danger to overcome them without some kind of resistance is suicidal. Don’t you think?

  5. This doesn’t help me at all. I get angry when I lose and I want to stop it with drugs because the feeling is pretty overwhelming. I can still think but I can’t turn it off or control it with any technique. I changes my whole personality and is coupled with a painful quasi-physical reaction in the middle of my body.

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