Isn't it weird that when you go to a psychiatrist for depression, they don't even run any blood tests?
But many don’t.
They simply talk to you for a bit, then give you a prescription and send you on your way.
Hell, they don't even scan and look at your brain, the very thing they are trying to treat.
You'd think that they would actually try to find something wrong with you and show that to you.
You know, like actually demonstrate that you have a "chemical imbalance" before trying to balance you out chemically.
But they don't.
They just throw pills at you and cross their fingers they will help.
Weird isn't it?
Some days I wake up and wonder how conventional psychiatry is even taken seriously.
It claims to be "science-based medicine" but it sure seems like quackery to me.
And even the National Institute of Mental Health (NIMH) is catching on.
The NIMH no longer funds research based on the Diagnostic and Statistical Manual (DSM) of Mental Disorders, which is the primary tool used by psychiatrists to diagnose people with psychiatric disorders.
Because they say the manual doesn't provide any data or evidence about the cause of mental illnesses, including depression (96).
Exactly – you deserve better.
The current state of psychiatry is essentially a bunch of doctors making diagnoses based on symptoms without actually testing to determine root cause.
And it’s time for a paradigm shift.
The mainstream medical literature is full of peer-reviewed studies that look at the underlying factors contributing to depression and other mental health symptoms.
Yet conventional psychiatry doesn’t pay attention to the findings of its own literature, or the literature of the other medical disciplines.
Psychiatrists simply ignore it.
But that doesn't mean you have to.
Why You Should Demand Blood Tests from Your Psychiatrist
I'll admit - when I originally started trying to figure out my depression, I also did a lot of guessing and not enough testing.
That made things much more difficult, and I ended up making a lot of mistakes along the way.
That's why I recommend you test more, and guess less.
Otherwise, it’s hard to know for sure what steps you should take to correctly treat and overcome your depression.
The underlying issues that contribute to depression are different for everyone.
But blood testing can show you the inner functioning of your body, highlight your physiological abnormalities, and help you identify the underlying root causes of your depression so that you can address them using nutrition, supplements, therapies and other lifestyle factors.
Below are 13 important blood tests that you should get done if you struggle with depression.
These blood tests shine light on some of the real, underlying root causes of depression, and will give you helpful information to act upon.
When something is outside the optimal range, you can then do something about it!
They put the power back into your hands, and give you a much better idea of where you should begin, so that you can get better faster, and overcome your depression sooner rather than later.
1. High-sensitivity C-reactive protein (hsCRP)
It’s obviously very important to test for CRP because an increasing amount of research suggests that depression is an inflammatory disease and many depressive symptoms may simply be a “side effect” of chronic, low-grade inflammation in the body and brain (93).
Yet how many psychiatrists test for CRP?
But you don’t have to wait around for them to check your levels.
If your levels come back high, you’ll need to take steps to fight back against the inflammation and dampen it.
My first recommended step would be to follow an anti-inflammatory diet.
My Free Grocery Shopping Guide for Optimal Mental Health is full of anti-inflammatory foods that you eat freely, and doesn’t include foods that are likely to increase your inflammation.
In fact, curcumin has been shown to be as effective as Prozac in treating depression, likely because of its anti-inflammatory effects.
Omega-3 fatty acids can also reduce inflammation. I personally take this krill oil supplement to make sure my brain gets enough.
2. Vitamin D - 25(OH)D
Vitamin D is a fat-soluble vitamin that your skin synthesizes when exposed to the sun.
In fact, one study found that 60 percent of the suicidal patients were deficient in Vitamin D. The patients also had higher inflammatory markers in their blood, suggesting that low levels of Vitamin D could be a cause of the inflammation (5).
Unfortunately, reports from across the world indicate that Vitamin D deficiency is widespread and a major health problem globally (1).
Researchers estimate that 50 percent of the general population is at risk of Vitamin D deficiency (2).
That’s why it’s so important to get your levels checked regularly (at least once each year).
If you have low levels, optimizing your Vitamin D levels can then reduce inflammation and improve your mood.
It’s best to get your Vitamin D by going outside and getting sunlight, but some people can’t get enough, especially during the winter.
3. Thyroid Panel
– Suzy Cohen, Pharmacist, Author of Thyroid Healthy: Lose Weight, Look Beautiful and Live the Life You Imagine
Your thyroid is a small butterfly-shaped gland located in your neck below your Adam’s apple.
It’s one of your most important glands, producing thyroid hormones – thyroxine (T4) and triiodothyronine (T3) – which impact the health and functioning of your entire body.
One of the most common causes of hypothyroidism is an autoimmune disease called Hashimoto’s thyroiditis, in which the body’s immune system attacks the thyroid tissue.
Here are some of the symptoms of low thyroid that I’ve personally experienced:
Sounds just like depression, doesn’t it?
That’s why I highly recommend getting done a complete thyroid panel.
A high-quality thyroid panel should measure Thyroid Stimulating Hormone (TSH), Free Triiodothyroine (fT3), Free Serum Thyroxine (fT4), Reverse T3 (rT3), and Thyroid Antibodies.
Some doctors will only test for TSH, but that is definitely not enough. Others will test for TSH, T3, and T4 but not assess the autoimmune status of the thyroid gland.
This lab test checks everything. It will show you if your thyroid is functioning optimally. No more guessing.
If you have low thyroid levels, treating the underlying hypothyroidism is critical to alleviating the depressive symptoms. Thyroid hormone replacement can often make people feel remarkably better and lift their depression completely.
Nutrition and lifestyle factors are also necessary steps in treating hypothyroidism.
Check out this post for the 13 ways that I’ve supported my thyroid and increased the production of my thyroid hormones over the years.
4. Vitamin B12
– Dr. James Greenblatt, Integrative Psychiatrist, Author of Breakthrough Depression Solution: Mastering Your Mood with Nutrition, Diet & Supplementation
Having sufficient levels of Vitamin B12 is necessary for your brain to work properly.
But deficiency is very common, especially in older individuals and vegetarians and vegans.
In fact, it’s estimated that almost 40% of Americans are deficient!
Research shows that if you are depressed, you likely have lower levels of B12 circulating in your blood, and people with low levels of B12 are also at greater risk of developing depression (6-7).
This happened to me. My levels were never tested. I was simply given medications, which further depleted my Vitamin B12 levels.
You can easily test your levels yourself by ordering this lab test.
If your levels are low, you will need to supplement with the methylated form of Vitamin B12 (methylcobalamin, or methyl-B12).
I’ve benefited from taking this methyl-B12 supplement before. If you decide to supplement, you should avoid the semisynthetic version of B12 (cyanocobalamin). Methyl-B12 is better absorbed and more biologically active.
I now take this B complex supplement regularly, and it includes methyl-B12.
Estradiol is an estrogen and the primary female sex hormone, responsible for the development and regulation of the female reproductive system.
It plays a significant role in the mental health of women.
There is a strong link between estradiol, mood and wellbeing. In fact, depression is correlated with sudden drops or fluctuations in estradiol, and long periods of sustained low levels of estrogen (8).
You can check your levels here.
6. Testosterone (Free and Total)
Conventional doctors didn’t test my testosterone because they assumed every a man in his 20s would have healthy levels.
But they were wrong.
Eventually I saw a functional medicine practitioner and he found out that I had the testosterone levels of an old man.
I was put on testosterone replacement therapy for almost one year to get my levels back to normal. And over that time, I saw a huge reduction in my depression.
And a systematic review and meta-analysis found that testosterone replacement has antidepressant effects in depressed patients (13).
If your levels are low, it would be wise to try testosterone replacement therapy, at least for a little while, until you find out why you have low testosterone.
7. Magnesium (Red Blood Cell)
Magnesium is a vital mineral that participates in more than 300 biochemical reactions in your body. This includes neurotransmitter and hormonal activity, all of which can have a huge effect on your mood.
If you have low levels, no worries; there are a number of ways to replete them.
I take this magnesium supplement.
Magnesium is one of the three nutrients that I think everyone should be taking because most people are deficient nowadays.
Stress depletes magnesium, and unfortunately, certain antidepressants drugs can actually further deplete magnesium as well!
On the flip side, magnesium has been shown to cause antidepressant effects by significantly increasing BDNF.
And research shows recovery from major depression in less than 7 days using 125 to 300 mg of magnesium (as glycinate and taurinate) with each meal and at bedtime (16-18).
That’s why I think doctors should be testing magnesium levels and prescribing magnesium supplements – which would be something that actually gets to the root cause of depression – rather than giving out antidepressants that cover up symptoms and actually make the underlying condition worse.
Homocysteine is an amino acid that is produced in the body as a by-product of methylation.
In healthy people, it’s properly metabolized and normal levels are maintained.
But when homocysteine isn’t properly metabolized, it can build up inside the body and levels can become too high.
And that’s when homocysteine becomes dangerous and unhealthy.
You can check your homocysteine levels by ordering this blood test.
If your levels are high, read this post for 16 ways to lower your homocysteine levels.
Zinc is an essential mineral for mental health, as it plays a key role in brain and nervous system function and neurotransmission.
Unfortunately, six different studies have found that even subclinical deficiency of zinc impairs brain function in children and adults, and it’s actually estimated that 2 billion people in the world are deficient in zinc (19-22).
So, if you struggle with depression, it’s quite possible that you’re deficient.
However, too much zinc isn't healthy either. That’s why it’s best to test instead of guess.
You can check your zinc levels by ordering this zinc blood test.
Put a teaspoon of the liquid in your mouth and mix it around
This is how I originally found out that I was deficient in zinc. During my initial test, the liquid tasted like water. After taking a zinc supplement for a while, I did the test again, and I had a very metallic taste in my mouth the second time around. It’s not as accurate as testing your actual levels, but it can still give you a good idea of where you stand.
However, if you’re deficient, I recommend at least short-term supplementation.
Several studies have shown that zinc supplementation has antidepressant effects and significantly reduces symptoms of depression. One way it does this is by significantly increasing BDNF levels (23-26, 28-29, 32).
I created and take the Optimal Zinc supplement to make sure my zinc levels are optimal.
Check out my previous post about zinc and copper if you’re interested in discovering more steps you can take to increase your zinc levels.
Zinc can also stimulate the vagus nerve.
10. Celiac Disease Panel
Celiac disease is a serious autoimmune disorder that occurs in genetically predisposed people.
When people with celiac disease eat gluten (a protein found in wheat, spelt, rye and barley), their body mounts an immune response that attacks and damages their small intestine.
It is estimated to affect 1 in 100 people worldwide, but celiac disease actually goes undiagnosed in 90% of cases, leaving them at risk for long-term health complications, including depression (46).
In fact, many people with celiac disease often struggle with depression.
One study found that major depressive disorder, dysthymic disorder, and adjustment disorders were more common in a group of celiac disease patients compared to controls (61).
And this was supported by follow-up studies (62-63).
Other researchers have found that celiac disease patients are more likely to be diagnosed with depression, but their depressive symptoms improve after following a gluten-free diet (64-65).
Yet many doctors never do.
Luckily, you can order your own blood test to check to see if you celiac disease, called the Celiac Disease Test Panel.
Even if you don’t have celiac disease, I highly recommend cutting out all gluten-containing grains from your diet for 30 days and see how you feel.
Dr. Kenneth Fine, a pioneer in gluten intolerance research, has demonstrated that 1 in 3 Americans are gluten intolerant, and that 8 in 10 have the genes that predispose them to developing gluten intolerance (47-49).
And for more than sixty years, reports in the scientific literature have linked wheat and gluten sensitivity to depression (50-57).
Following a gluten-free diet significantly improves my mood (even though I didn’t have celiac disease or any digestive issues).
I completely cut it out seven years ago, and within a few weeks, I felt so much better mentally.
I also lost a bunch of weight and my asthma disappeared.
I haven't touched it again since.
In one study, depressed patients who didn’t have digestive issues (like me) followed a gluten-free diet, and within 2-3 months, they experienced a reversal of their depressive symptoms (58).
Researchers have also found that a gluten-free diet improves depression by increasing levels of l-tryptophan – the precursor to the neurotransmitter serotonin (59).
Another study found a significant increase in serotonin and dopamine because of the removal of gluten (60).
Clearly, there is more to gluten than celiac disease, and cutting out wheat is one of the first dietary steps I recommend to people who are striving to overcome depression.
Try it out. You’ll like feel better.
And when you’re done, here are two other foods I recommend avoiding if you have depression.
The bacteria in our guts can determine the degree to which we are sensitive to foods such as gluten, so you should also try to increase the good bacteria in your gut.
11. MTHFR DNA Analysis
Methylation is one of the most important processes in your body and brain.
The methylation cycle plays a key role in the synthesis of melatonin, coenzyme Q10, and neurotransmitters such as serotonin and dopamine.
Methylenetetrahydrofolate reductase (MTHFR) is one enzyme that plays a very important role in the methylation cycle.
Most importantly, the MTHFR enzyme helps produce l-methylfolate in the body.
In fact, numerous studies have shown that MTHFR mutations are significantly associated with depression. And more than one meta-analysis has found that people with MTHFR mutations have an elevated incidence of depression (68-77).
There is also a decrease in serotonin synthesis in patients with MTHFR mutations (71-72).
You can check to see if you have mutated copies of the MTHFR gene here.
Why is this so important and what should you do about it?
Therefore, you require higher levels of folate and should supplement with l-methylfolate, the activated form of folate.
You can get l-methylfolate here.
This will give your brain the form of folate that it needs to function properly. You’ll essentially skip the enzymatic/genetic problem.
Whatever you do, don’t supplement with folic acid. It’s a waste and will cause more harm if you have a mutation.
Testing your homocysteine levels will also let you know if your methylation pathway is working properly.
Lyme disease is an infectious illness caused by the bacterium Borrelia burgdorferi, which is spread by ticks (78).
Lyme disease can lead to psychiatric symptoms, including severe depression and suicidal thoughts (79-80, 83-84).
Depressive states among patients with late Lyme disease are fairly common, ranging from 26% to 66% in studies (82, 85).
Researchers have even concluded that depression in patients with Lyme encephalopathy is caused by central nervous system dysfunction and cannot be explained as a psychological response to chronic illness (81).
That’s why it’s critical to rule out Lyme disease if you’re feeling depressed.
It can sometimes be hard to ask for your doctor to test for it.
But you can check yourself by ordering this blood test.
13. Fasting Glucose, Insulin and Hemoglobin A1C
If you’re struggling with depression, it’s also important to check your blood sugar control.
Unstable blood sugar can contribute to a number of different mental health problems, including depression.
Researchers have found that impaired fasting blood sugar is a significant predictor of depression (86).
One study found that men with undiagnosed type 2 diabetes had nearly double the odds of major depression (90).
A fasting insulin blood test is also important, as it tells you how your pancreas is working when you’re not eating anything.
Research shows that depressive symptoms are associated with fasting insulin resistance (91).
You can order a fasting insulin test here.
Lastly, Hemoglobin A1C may be the most important test, as it gives you the average of your blood sugar levels over the past three months.
And researchers have found that variability in blood sugar control is significantly associated with more depressive symptoms (92).
You can order the Hemoglobin A1C test here.
Making dietary changes to control blood sugar is critical.
Check out my Free Grocery Shopping Guide for Optimal Brain and Mental Health for the best foods to eat in order to manage your blood sugar and improve your mood.
How to Order These Tests Yourself (If Your Doctor Doesn’t)
Overall, optimizing your mental health and overcoming your depression really relies on having accurate data about your specific biochemistry.
And the above lab tests are a great way to learn about your body so that you can correct the underlying problems that are contributing to your depression.
You can go to your doctor and ask for them, but don’t be surprised if your doctor tells you they aren’t necessary and won’t order them for you.
You may have to put up a fight.
I’ve had to do that many times when I’ve requested different blood tests.
But if you’re not feeling well, it’s worth advocating for yourself.
Tell your doctor that you want a baseline assessment before taking medication.
Remember, your doctor should be working for you.
If you get fed up, just “fire” your doctor and find a new one – one that will actually work with you and for you.
If all else fails and you can't find a doctor to run these tests, you can always just skip doctors completely and order the blood tests yourself, which can actually end up saving you a lot of time and hassle.
True Health Labs is a reliable and trustworthy way to do this online.
They provide direct access to blood tests from certified laboratories in the US, Canada, Europe and internationally. All blood tests are “direct-to-consumer”, meaning they allow you to pick and choose the blood tests you’d like, no doctor required.
Doctors shouldn’t have exclusive rights to information about your body anyway.
No one has a greater right to your blood test results than you do, and you should be able to access blood test results directly from the company you pay to run the labs.
Overall, there is no doubt that having direct access to blood testing, and direct access to your results, is an invaluable way for you to take control of your brain and mental health.
Great treatment starts with great testing, providing you with the information you need to put your health back into your own hands.
In summary, here are all the blood tests I recommend you test for:
Once you order the tests and get the results, True Health Labs also offers a one-on-one results review with one of their functional medicine doctors. They can help you accurately interpret your blood test results and determine the diet and lifestyle modifications that will effectively bring the results back into an optimal range.
Alternatively, you can book a consultation with me or find a naturopath, integrative or functional medical practitioner in your area.
And if you live in the United States, I've also heard good things about WellnessFX. They also provide direct-to-consumer access to many of the blood tests above, as well as phone consultations with health practitioners. You can learn about the different blood test packages they offer here.
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About the Author
Jordan Fallis is a health and science journalist and researcher, and the founder of Optimal Living Dynamics, a website that has helped more than 1.5 million people improve their brain and mental health. His work has been featured in the Canadian Broadcast Corporation, the Canadian Medical Association Journal, and the Canadian Pharmacists Journal. Jordan has also interviewed, consulted, and worked with more than one hundred medical doctors, health practitioners and leading researchers. He spends a lot of time scouring medical research, writing about what he finds, and putting the theories to the test on himself.
Medically reviewed by Dr. Fred Hui, MD, CCFP, CAFC