In the UK women are twice as likely as men to be diagnosed with a mood disorder – depression, generalised anxiety disorder, social anxiety disorder or panic disorder. Oestrogen and progesterone are the main female sex steroid hormones. In addition to their roles in the female reproductive system, both are known to regulate neurotransmitter activity in a number of ways.
Oestrogen & Serotonin
Serotonin is known as the happiness neurotransmitter, and low levels are associated with depression and anxiety. Genetic variances (SNPs) can impact our ability to make, use and break down serotonin, thereby increasing susceptibility to low mood. SNPs on the TPH1 (tryptophan hydroxylase) gene can slow down serotonin synthesis, and SNPs on the MAOA (monoamine oxidase A gene) can increase the break down of serotonin, both contributing to lower serotonin levels.
Oestrogen can support serotonin levels by:
[1] promoting TPH1 activity (helping to make serotonin); increasing sensitivity to serotonin (helping to make more serotonin receptors)
[2] most importantly, reducing MAOA activity – thereby slowing the removal of serotonin.
Oestrogen & Dopamine
Dopamine is the reward and pleasure neurotransmitter that helps to motivate us to take action. As with serotonin, genetic SNPs can affect dopamine level and response, and oestrogen has a dopamine promoting effect. High dopamine can make you feel over-stimulated, impulsive, angry and/or crave more dopamine (addictive behaviours).
Both MAO and COMT genes impact the rate at which we break down, and remove, dopamine. In particular, SNPs on the COMT gene can have a strong impact on dopamine levels. The so-called ‘ValVal’ genotype is associated with lower dopamine and a ‘MetMet’ genotype with higher dopamine. Neither of these genotypes are ‘good’ or ‘bad’ on their own, but are dependent on context of other factors such as nutrition, stimulants, stress and oestrogen. As oestrogen ‘supports’ dopamine levels it contributes to higher dopamine.
Swings & Roundabouts
Although some people are naturally ‘low’ or ‘high’ serotonin or dopamine ‘types’, due to genetics, most of us are somewhere in the middle. There is a higher risk of experiencing mental discomfort and mood disorders if, and when, neurotransmitter levels are particularly high or low or fluctuating.
In women, more so than men, levels of sex steroid hormones vary both through life stages – puberty, pregnancy, postpartum, perimenopause and menopause, and monthly (through menstrual cycles).
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