PCOS and Depression: They May Have the Same Root Cause

By Clare Goodwin

Last updated: September 3, 2020

Suffering from PCOS and depression? They may have the same root cause.

If you look on any PCOS forum you’ll read countless posts from women suffering from mental health conditions like depression and anxiety. The statistics are mind-boggling, with some studies reporting that up to 64% of women with PCOS suffer from depression (1). 64%! That’s an incredibly high number compared to only 5% of the general population. 64%! That’s an incredibly high number compared to only 5% of the general population.

So what’s going on here? Are we just the unlucky recipients of unrelated chin hairs and depression? No, I don’t think so. But not because of the reasons that you may have been led to believe…

Many researchers have suggested that the undesirable symptoms of PCOS lead to the high incidence of PCOS and depression. Weight gain, hair growth, acne and infertility – who wouldn’t be depressed!?
I don’t disagree that emotional and psychological factors play a part in depression, although Horwitz and Wakefield would argue in their book “The Loss of Sadness: How Psychiatry Transformed Normal Sorrow into Depressive Disorder”, that this is normal sadness, not depression.

Researchers suggesting that undesirable symptoms of PCOS lead to depression is like saying that the reason anyone has depression is because they are poor, unmarried, or don’t have a six pack. Ernest Hemingway would turn in his grave.

Clinical depression can happen to a supermodel who’s popping out triplets while sitting on a beach in Thailand. It happens regardless of whether you’re worried about sprouting chin hairs or not. Clinical depression is an incredibly deep-seated physiological process. A very good paper, published in the Journal of Fertility and Sterility, demonstrated this perfectly. Researchers took a group of 135 women with PCOS and screened them for depression, also accounting for their symptoms and circumstances. They screened for things such as:

  • Marital and employment status
  • Level of education
  • Whether they had hirsutism, acne, or were overweight
  • Levels of insulin resistance and testosterone
  • The presence of acanthosis nigricans (dark velvety patches in the folds of the skin), as another marker of insulin resistance.

The results?

They found that while 64% of the women with PCOS had depression, there was no correlation between occurrence of depression and the severity of their PCOS symptoms or social situation. Women with hair growth, acne, weight gain were no more likely to get depression than women without those symptoms (1).

What is the Connection Between PCOS and Depression?

I’m sure you’ve heard that depression is a chemical imbalance in the brain (particularly of serotonin and norepinephrine). So you would be right to question how a ‘hormonal’ issue like PCOS can cause a chemical imbalance.

You might be interested to know that there is actually very little research to support the chemical imbalance theory. If it was just too little serotonin and norepinephrine then everyone with depression would have low levels of these chemicals. But this isn’t the case. Although some depressed people have low levels of serotonin and norepinephrine, the majority do not. Several studies indicate that only 25% of depressed patients have low levels of these chemicals (2).

The chemical imbalance theory is what helps to sell medication. The antidepressant market is worth $10 billion in the U.S. alone, so you’re not going to hear big pharma refuting this theory (3).

Depression as a Symptom of Inflammation

A new theory proposes that depression is not a disease, but a symptom of chronic inflammation (4). Inflammation is also at the heart of most PCOS cases. I’ve written a full article about inflammation and PCOS but in summary, chronic inflammation is when your immune system is ‘turned on’ all the time. Inflammation is a normal and essential function, but it’s only supposed to be turned on for brief periods of time. When it’s constantly activated then it begins to causes issues.

Imagine your immune system as an army, fighting a war against foreign invaders. Just like any army, if it’s fighting on the front line for too long then that’s going to start taking it’s toll. The soldiers will get exhausted and make mistakes and that has a knock on effect. Similarly, when your immune system is chronically activated then that affects all the cells in your body.

During an inflammatory reaction, chemicals called “cytokines” are produced. Inflammatory cytokines produce a variety of symptoms that are exactly the same as depression (4). Interestingly, antidepressants (particularly SSRIs) have been shown to reduce the production of pro-inflammatory cytokines (5). This may be the mechanism in which they act to reduce depression symptoms (6).

One study showed that artificially inducing inflammation in healthy people led to them developing depressive symptoms (7). Inflammatory markers, such as CRP, are approximately 96% greater in women with PCOS (8). It’s therefore likely that inflammation could be driving the high incidence of depression in PCOS too.

What Causes Inflammation?

I’ve written a comprehensive article on inflammation and PCOS that you can find here, so I won’t repeat that content. Here are three other causes that I didn’t mention in that article:

1. Insulin Resistance

70-80% of women with PCOS have insulin resistance (9). However, most women don’t know whether or not they have it because they’ve only had a blood glucose or HbA1C test. Neither of these tests are sensitive enough to pick up early stage insulin resistance.

Insulin resistance and inflammation go hand in hand: inflammation can cause insulin resistance and insulin resistance can cause inflammation. Insulin resistance causes your ovaries to overproduce testosterone (the crux of PCOS symptoms). You may not know whether you have insulin resistance or not, but the most obvious symptom is if you put weight on around your belly.

Read my article about PCOS and insulin resistance for more information.

2. Vitamin D Deficiency

Vitamin D is the ‘sunshine hormone’ and those of us living further from the equator are chronically low in vitamin D. Women with PCOS are even more at risk, with one study finding that up to 44% of women with PCOS are severely vitamin D deficient. Severe vitamin D deficiency was found to only affect 11% of women without PCOS.

Vitamin D has been linked with depression. The likely mechanism is that vitamin D helps to reduce the inflammatory markers that I mentioned above (10). If you live far from the equator then make sure that you’re consuming lots of fatty fish to make up for the lack of sun in the winter!

3. Too Little Sleep

Studies have shown that 10 nights of sleeping for only four hours caused a 5 fold increase in inflammatory markers (11). Chronic sleep loss is also a well-known contributing factor to developing depression in the first place (12).

How much sleep is enough? Don’t get confused by the four hour study, this is just the amount they used in these trials to induce inflammation. If you want to know how much you personally need, the best way is to practice going to bed without an alarm and seeing how long you sleep for. For me, this is about 8.5-9 hours.

Finally, Depression Could Be the Result of Something More Sinister

I recently had a patient who came to me as she was suffering from some gut health issues. She also had a family history of bowel disease. She mentioned in passing that she was on antidepressants.

When I conducted a full metabolic assessment, I found that not only was she suffering from gut health issues, but also had symptoms of hypothyroidism, blood sugar dysregulation and nutrient deficiencies. We eventually found that she had a form of hypothyroidism called Hashimoto’s Thyroiditis, an autoimmune condition which is a state of chronic inflammation

Depression or lack of motivation is actually a symptom of hypothyroidism (13) – it’s one of the main symptoms that I look for. By simply accepting a diagnosis of depression and then taking antidepressants to treat it you could be failing to treat the actual root cause of it. It therefore pays to look deeper your condition, as treating the root cause can resolve all symptoms, not just depression.

In this case, antidepressants completely missed part of the reason that she was depressed. So it always pays to look deeper as treating the root causes can resolve all the symptoms, not just depression.


(1) Prevalence of Depressive Disorders in Women with PCOS
(2) Serotonin and Depression
(3) Antidepressants: A Complicated Picture
(4) Cytokines and Depression
(5) Antidepressants and Pro-Inflammatory Cytokines
(6) Negative Immunoregulatory Effects of Antidepressants
(7) Cytokine-Associated Disturbances in Humans
(8) Circulating Inflammatory Markers in PCOS
(9) PCOS and Insulin Resistance
(10) Vitamin D Deficiency in PCOS
(11) Effect of Sleep Loss on Inflammatory Markers
(12) Sleep and Depression
(13) Hashimoto’s Thyroiditis