Serotonin und Unterschiede zwischen Mann und Frau

Studien legen nahe, dass Serotonin bei Frauen und Männern unterschiedliche Reaktionen hat:

Less Serotonin Means Depression for Women and Impulsiveness for Men

Recent study published in Biological Psychiatry focuses on significant changes in sex and genes what concerns the way both men and women respond to decrease in serotonin function, especially regarding mood and impulsivity of both genders.

Together with his colleagues, Dr. Espen Walderhaug, one of the authors of the research, used a special technique on healthy patients. The technique is entitled acute tryptophan depletion. It is meant to decrease the levels of serotonin in the brain. Researchers found that men turned out to be more impulsive; however, they did not experience any changes in their mood.

Apart from men, researchers found that women had a worsened mood, they becoming more cautious. Such reaction is often linked to depression. Scientists also found that the effect of mood worsening in women was powered by deviation in the promoter region of 5-HTTLPR, which is a serotonin gene, known as transporter.

What researchers have found outlines the complexity of both studying and treating these issues. Dr. Walderhaug stated that the findings of the research performed by his team „might be relevant in understanding why women show a higher prevalence of mood and anxiety disorders compared to men, while men show a higher prevalence of alcoholism, ADHD and impulse control disorders.“

Brain’s serotonin system differs between men and women

A research group at Karolinska Institutet has now shown using a PET scanner that women and men differ in terms of the number of binding sites forserotonin in certain parts of the brain.

Their results, which are to be presented in a doctoral thesis by Hristina Jovanovic at the end of February, show that women have a greater number of the most commonserotonin receptors than men. They also show that women have lower levels of the protein that transports serotonin back into the nerve cells that secrete it. It is this protein that the most common antidepressants (SSRIs) block.

“We don’t know exactly what this means, but the results can help us understand why the occurrence of depression differs between the sexes and why men and women sometimes respond differently to treatment with antidepressant drugs,” says associate professor Anna-Lena Nordström, who led the study.

The group has also shown that the serotonin system in healthy women differs from that in women with serious premenstrual mental symptoms. These results suggest that the serotonin system in such women does not respond as flexibly to the hormoneswings of the menstrual cycle as that in symptom-free women.

Women More Depressed And Men More Impulsive With Reduced Serotonin Functioning

Using a technique in healthy participants called acute tryptophan depletion, which decreases serotonin levels in the brain, Walderhaug and colleagues found that men became more impulsive, but did not experience any mood changes in response to the induced chemical changes. However, women in this study reported a worsening of their mood and they became more cautious, a response commonly associated with depression. The researchers also discovered that the mood lowering effect in women was influenced by variation in the promotor region of the serotonin transporter gene (5-HTTLPR).

One of the study’s authors, Dr. Espen Walderhaug, explains, „We were surprised to find such a clear sex difference, as men and women normally experience the same effect when the brain chemistry is changed… Although we have the same serotonergic system in the brain, it is possible that men and women utilize serotonin differently.“

Hier ist ein interessanter Beitrag dazu, wie Serotonin zu einer Depression führen könnte:

Let’s start with serotonin. Serotonin is a neurotransmitter (a chemical messenger) which is found ALL over your body. It has major effects in the gut, but most people like it for its effects in the BRAIN. Most particularly for its effects on mood and our processing of emotions. Most antidepressants on the market today (like Prozac and Celexa and others) work by targeting the serotonin system, blocking a molecule that recycles serotonin, and thus keeping serotonin around and increasing its levels in the brain.

Now, I mostly deal with the mechanics of how we think antidepressants work (via things like increased serotonin or increases in the birth of new neurons in the brain), but there are also psychological theories as to how antidepressants work, in how they affect your thought processes. These affected thought processes will always have a physical basis of changes in the brain, but as yet the two mechanisms haven’t really connected.

Right now, the hypothesis is that antidepressants exert their physical effects on the brain, and these effects change how you perceive things around you, and how you REMEMBER things that have happened to you. Some scientists think that depression (which also comes down to physical changes in the brain, we just don’t know what they are yet) is characterized by a negative outlook on life. Well, duh, you might think. But it’s more than just that. It’s a negative outlook on the way you perceive things, causing negative bias. When someone looks angry, for example, a person without depression may think they just look angry at something, while someone with depression might assume the angry person is angry at THEM, whether or not they actually are. Not only that, depression can put a negative cast on how you think of things in the past. You may remember someone frowning, and while someone without depression may think they were disappointed about something, someone with depression will think the person is disappointed with THEM, specifically. People with depression pay less attention to happy faces, and even interpret neutral faces as sad, which suggests that they have a significant negative spin on their emotional processing. This effect is usually referred to as rumination, where someone focuses their attention on negative perceptions and memories.

Weniger Serotonin würde daher bei Frauen dazu führen, dass sie schlechter gelaunt sind und daher Aktionen eher auf sich beziehen. Was dann vielleicht auch eine gewisse Dünnhäutigkeit vieler Frauen erklären könnte.

Zumal der Serotoninspiegel auch innerhalb des Zyklus schwankt:

Women’s brain chemistry is highly receptive to hormones. The impact of both estrogen and progesterone creates changes in the brain leading to disturbed mood. As Sichel and Driscoll have written, in their excellent book, Women’s Moods, the estrogen-serotonin connection is “the critical vital component” in understanding what women need in order to sustain mental health. As such, alas, it remains “invisible and unacknowledged.” Far to few clinicians in the medical and mental health professions are knowledgeable about the effect of hormone changes on women’s mental health.

Estrogen is responsible for maintaining the orderly firing in the brain of a number of neurotransmitters–dopamine, norepinephrine and acetylcholine, as well as serotonin. This orderly firing is what sustains a balanced mental state.

Estrogen can be thought of as the body’s own antidepressant and mood stabilizer. When estrogen levels rise (as they do each month, for example, when menstruation begins), serotonin levels rise too, and mood improves. When estrogen drops (and along with it, serotonin), the reverse happens: mood becomes negatively affected negatively.

As we know, a fair percentage of women have a rough time with anxiety and depression, premenstrually, when their estrogen and serotonin levels are low. (Note that these levels drop off suddenly, at mid-cycle, precisely when ovulation begins). The sky-high levels of estrogen during pregnancy often produces enhanced mood states. But these booming levels drop off dramatically within hours of the baby’s delivery, causing an abrupt and potentially rather drastic shift in serotonin. This is the very action that triggers post-partum depression (and we now know that post-partum depression affects a much higher percentage of women than used to be recognized.) It is the same action that causes anxiety and depression at the time of menopausal change–the fall-off in estrogen affects sertonin levels.

Das System an sich scheint noch nicht so ganz erforscht zu sein. Es scheinen aber zumindest deutliche Unterschiede zwischen den Geschlechtern vorhanden zu sein. (zur Wirkung des Serotonins bei der Liebe vergleiche „Lust, Anziehung und Verbundenheit oder auch Liebe“, die deprimierende Wirkung des niedrigen Serotoninstandes wird dort durch allerlei andere Hormone ausgeglichen, insbesondere auch durch Dopamin. Es bleibt insoweit die Wirkung zurück, nach der sich Handlungen auf einen selbst beziehen, allerdings hier im positiven Sinne, wenn ich es richtig verstehe).

4 Gedanken zu “Serotonin und Unterschiede zwischen Mann und Frau

  1. @Galloway

    Ich vermute, dass da noch interessante weitere Sachen zu entdecken sind, wenn man das näher erforscht.
    Bei Männern entsteht ein Handlungsdrang, bei Frauen eher eine schlechte Stimmung, das sind ja schon mal deutliche Unterschiede. Zumal Serotonin auch am Stressabbau beteiligt ist, was sicherlich auch interessante Unterschiede ergibt.

    Bei ADHS könnte es wie du richtig sagst auch eine Rolle spielen. Und deswegen könnte es eben auch wichtiger für Jungs sein sich zu bewegen.

  2. Pingback: „Extra Pair Copulation“ oder „Mit einer anderen schlafen wollen“ « Alles Evolution

  3. Pingback: Übersicht: Evolution, Evolutionäre Psychologie und Partnerwahl | Alles Evolution

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