2018 UPDATE: Since I first wrote this blog, further research has refined my position on this topic. It’s worth noting that the menstrual cycle is more of a ‘trigger’ of symptoms, rather than the direct cause. For example, research suggests that it is not the level of sex hormones that influences an individual’s health, but it could be related to the physiological changes involved in the menstrual cycle e.g. water retention, blood sugar changes, blood pressure changes, and reactions to pain and inflammation. This is why most people who menstruate do not experience significant symptoms, or mood changes. However, I still believe that further research on the menstrual cycle could be invaluable in learning more about such physiological ‘triggers’ of mental health disorders.
It is well known that the menstrual cycle can affect an individual’s mood and anxiety levels…
However, the potential relationship between what happens during the menstrual cycle and anxiety and depression, has largely been ignored by medicine. This blog post highlights why we ought to pay more attention to the role of the menstrual cycle in the study, diagnosis, and treatment of anxiety and depression, for the benefit of all people suffering from these issues.
1. The crossover of menstrual cycle-related symptoms with those of anxiety and depression
The majority of the most commonly experienced menstrual cycle-related symptoms are also those associated with depression and anxiety (see table above). This suggests that they may share a common underlying cause, perhaps indirectly relating to changes in ‘female’ sex hormone levels (oestrogen and/ or progesterone).
In fact, it is known that if a cyclical pattern in an individual’s symptoms of anxiety and/ or depression is identified (by tracking symptoms over time), then suppressing ovulation (i.e. using hormonal medications or devices) can be a more effective course of treatment than antidepressants, or anti-anxiety medication .
Note: All humans have both ‘male’ and ‘female’ hormones, in varying levels. Male humans tend to have much higher levels of testosterone and other androgens, and female humans tend to have much higher levels of oestrogens and progesterone (see point 4 for further information).
2. The prevalence of anxiety and depression in the general population
Women (or, more specifically, people with a female reproductive system) are statistically more likely than men (people with a male reproductive system) to suffer from a range of mental health issues. In fact, a recent investigation into 12 different national population studies  revealed that:
- Women are significantly (up to 40%) more likely to experience anxiety and depression.
- Women are also more likely to experience a phobia, eating disorder (anorexia and bulimia), PTSD (Post Traumatic Stress Disorder), and insomnia.
- Men and women are more equally at risk of psychiatric disorders such as schizophrenia, OCD (Obsessive Compulsive Disorder), or bipolar disorder.
- Men are more likely to be affected by antisocial personality disorders, or alcohol and substance abuse.
The authors suggest that some of these sex differences can be explained by social and environmental factors, but there might also be physiological factors at work.
3. The timing of mental health issues
- The female-prevalence of anxiety and depression is known to start at puberty, with this gender difference absent in child mental health, and reducing in older age (from approx. 65 years) .
- We also know that in people who menstruate, depression is far more likely to occur at times of hormonal flux- puberty, during the menstrual cycle, pregnancy, after giving birth, and in the 1 or 2 years before periods cease (known as the perimenopause) .
- Some research even suggests that people who menstruate are more likely to attempt suicide at certain times of their menstrual cycle – when oestrogen and serotonin levels are both at their lowest (see point 4) .
These patterns suggest a relationship between fluctuating levels of ‘female’ sex hormones and the symptoms of anxiety and depression (among others). This helps to explain why improved overall hormone balance (through diet, or hormonal therapy) can significantly alleviate these symptoms.
4. Sex hormones influence stress and depression-related hormonal pathways
- There is some evidence to support the idea that testosterone therapy might work as a treatment for depressed men, although studies have produced inconsistent results. It is, however, more generally agreed that testosterone may act as a ‘protective’ factor against developing depression in both women and men .
- Oestrogen can alleviate the symptoms of depression , and boost both dopamine  and serotonin  levels, which are critical hormones involved in mood regulation .
- Oestrogen levels have been found to be lower in people who experience severe depression during particular times of the menstrual cycle .
- The sudden reduction in the levels of both oestrogen and progesterone is linked to the depression and anxiety experienced by some individuals after giving birth . Oestrogen withdrawal is linked to low mood, whereas progesterone withdrawal is linked to anxiety .
- Both testosterone and oestrogen affect the response of the ‘stress axis’ (technically known as the hypothalamic-pituitary-adrenal (HPA) axis), but in women, the stress response tends to activate more rapidly and produces a greater output of stress hormones .
- Interestingly, repeating or chronic activation of the stress axis, decreases oestrogen and testosterone production . This may explain why people suffering from stress can become trapped in a vicious cycle, as constant anxiety levels reduce their ability to produce anti-anxiety hormones.
So, there is quite possibly a relationship between the menstrual cycle and the symptoms of depression and anxiety.
Considering all that we have learnt above, the menstrual cycle, rather than being a taboo subject, should be seen as offering a plentiful and regular opportunity for researchers to further investigate the underlying causes of anxiety and depression.
Doctors should be more aware of the relationship between the menstrual cycle (and hormonal medications) and the symptoms of anxiety and depression. For example, tracking symptoms over time can help establish if the menstrual cycle is triggering, or worsening, a mental health condition.
If so, treatment options can include dietary changes, and/ or hormonal therapy, rather than the more usual prescription of antidepressant, or anti-anxiety, medication, which may be less effective and more likely to result in unwanted side-effects .