Depression Community
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351317 tn?1204751871

why don't they blood test for serotonin levels?

Why don't they blood test for serotonin levels? Couldn't this help differentiate between a chemical depression and situational one?
52 Responses
362387 tn?1207274119
I wish they had that kind of test.  Seems like they should this day in age.   It sure would help me right now.
Avatar universal
I know in theory that sounds logical, but it doesn't work like that.

It is the reuptake of Serotonin in the brain that can cause depression, not the actual level or amount in the brain.

For example you could have perfectly normal levels of Serotonin in your brain, but if the receptors in your brain are performing the reuptake (a kind of absorbsion) of that Serotonin too rapidly then much less Serotonin is left in between the receptors and this inhibits the brains ability to function normally, which can result in a depressed brain.

Not to mention that Serotonin reuptake is not the only contributing factor related to depression. many other neurotransmitting chemicles also play a big part in brain function. Sush as Neurephineferine, Doapamine, and Triptafane, just to name a few.

It's important to remember that SSRI drugs such as Prozac, Zoloft, Paxil, Lexapro, Ect.... Do not raise the level of Serotonin in the brain. Rather they work by Inhibiting the reuptake of Serotonin that already exists in the brain, Thus resulting in a slightly higher build up of Serotonin to remain in stasis between the billions of receptors in the brain. this inhabition of reuptake allows for improved brain fuctioning as it relates to mood and well being because more Serotonin is left in stasis between the receptors of the brain that rely on this presense of Serotonin to properly fire. Think of it like a tiny bit of fuel in between two slightly spaced apart receptors. The receptors need this Serotonin as a kind of bridge to fire data back and forth. When the Serotonin is artifically (with meds) prevented from being absorbed by the brain, more of it can stay in the little places between the receptors to do what it does best, act as a bridge for firing data to different parts of the brain.

To take any drug that is designed to increase the amount of Serotonin in the brain is very dangerous. These drugs do exist. For example the drug Ecstacy does this very well.
The problem with taking a drug that directly pumps Extra Serotonin into the brain is that eventually your body will do what it does best..... It will stop naturally producing Serotonin because it is getting it artifically. For this to happen would be a nightmare scenario and could result in eventual brain damage.

There have been some huge advances toward a working test that can give doctors a better idea of which antidepressant will work best for each individual. This would take a lot of the guess work out of finding the right AD medication for your individual biology.

It's still the the testing phases, but I realy think we will see this test approved by the FDA in the next few years. The accuracy of the test is whats going to be the big determining factor in it's success.

351317 tn?1204751871
Well if the amount of serotonin in your brain is already low why would a drug that helps reuptake like SSRI's make much of a difference? Could this be why people get rebound effects or suddenly a med will stop working because the brain adjusts to the extra serotonin in the brain unable to be absorbed and stops producing enough to even fill those gaps. Much like Alzheimer's patients who take L-dopa "synthetic dopamine" they keep having to up the dose because the body will adapt over time. Maybe if you could trick the brain into keep releasing the current amount of serotonin and take synthetic serotonin maybe that could prevent the rebound cycle.
Avatar universal
SSRI's don't help reuptake of Serotonin, they do just the opposite, they inhibit the reuptake of Serotonin. It's this inhibition effect that slowes the reuptake process, which in turn allows for higher levels of Serotonin to build up in the brain.

It's kind of like finding a back door to raising Serotonin levels without introducing a chemical to the system that directly forces a flood of serotonin to be produced artifically.

Scientists could easily make a drug that simply and directly raises levels of Serotonin in the brain. The problem with that approach is that to do so would have very serious long term effects on proper brain function.

For example, if I were to inject you with an artifical hormone that your body already produces naturally and I did this for several months, the end result would be that your body would say, "well, I'm getting plenty so I can shut down making anymore."

Then if the injections were stopped, there is a good chance your body may not start producing that hormone again. At least not in sufficient levels to keep you well.

The same thing could happen if pure Serotonin were taken. The results could be devistating.

This action is much different than our bodies ability to build resistance to drugs and alcohol. SSRI meds and other AD medications often poop out in time.
This is why you see so many people having to change meds that once worked well for them.

Our bodies are amazing machines and they are very good at learning how to destroy any Chemicle or drug that is not native to it. Some peoples bodys do this very fast and others are slower at it. My body happens to be very good at building resistance to any medication I put in it. I get maybe 1 year on any one AD medication before my body renders it usless.

Avatar universal
I am frustrated and confused, maybe you can shed some light please.
I had an anxiety attack that landed me in the hospital for 24 hours.   First time in my life and didn't know what it was, thought I was having a severe allergic reaction or heart attack.   That was back in July and I'm just "slightly" feeling better since then.     I've been taking Buspar and feel anxious, tense, weepy every day and have HOT/BURNING spots in different areas of my body sporadically.  The heat build up in my body drives me crazy, is that too much serotonin or what could it be?   Have you ever heard of that ?  My email is ***@**** if you could please respond.  I cant get any answers from doctors.  Thank you !  
Avatar universal
Buspar or "buspirone hydrochloride." is an anti-anxiety agent. It's not a Benzodiazaphine like Xanax or Valum. Thus it is considered better for the "long term" treatment of anxiety dissorder.

That is if all you suffer from is anxiety dissorder. About 60% of people that suffer from Anxiety dissorder also suffer from Major cronic depression. About 85% of people that suffer from Severe Depression also suffer from Anxiety dissorder.

So now you see how common it is for the two dissorders to play together.

Depression and anxiety are like two little peas in a pod. They both need each other to survive. Alone they are less powerful and they know this very well. That's not to say that both don't need to be treated.

You may not have been properly disagnosed, and as such you may not be getting the proper medication which can = trouble for you and your condition.

Not sure if your doctor is an expert in Mental health, but if he isn't may I suggest you find a Psychiatrist ASAP so that you can get proplerly treated and feel better.

Please refer to the post I just made on the boards about Regular doctors & Psychiatrists. There is a huge difference.  
Avatar universal
Thank you , thank you, thank you for the response and clear explanation !  
Avatar universal
Seems what we need is a test to measure how well the brain receptors are working - wouldn't this help determine whether or not depression was caused by a chemical imbalance?
Avatar universal
I agree 100% and there are very brilliant Psychiatrists and Psychopharmocologists contuing to work on more exacting test that are accurate enough to make a determination between situaltional depression and the type of cronic depression that is caused by actual brain malfuction in the mood receptors of our brains.

The main and most difficult part about the development of such tests is the sheer complexity of the human brain.

My Psychiatrist once told me that current treatment with psycotropic meds is more of an art, rather than an exact science.

He alos told me that current top notch Psychiatry only understands about 10% of how the disease of cronic depression and anxiety manifest in the brain. He also mentioned that currently there are about 4 known chemical neurotransmitters in the brain that they know of which effect mood regulation. He also stated that there are many more, in fact dozens more of these mood regulating neurotransmitters that have yet to be discovered.

My P-doc also told me that in the next 10 years there will be an absolute revolution regarding the treatment of very severe uni-polor and bi-polor types of depression. He said that science is just on the cusp of cracking the code to why depression effects so may people and this will result in better medications and better treatments.
874521 tn?1424116797
Hensley u have alot of valuable medical knowledge, is this from personal experience or r u in the medical field?
I have never had that question answered for me before....I too can only take an antidepressant for approx a year than it no longer works...I never knew why b4. I always assumed I was just atypical.
Over the years my psych has trialed  many meds and now I am on lamotrigene although I can say I sure didn't have any faith in the dx of bi-polar...but the drug has worked good,(so far)its been almost 16 months now and thats long for me.
Interesting and I would appreciate any material u may have on info regarding expanding beyond BP 1&2  to 3&4.
I really don't feel I fit into the symtoms of either BP 1or2...so I would be most interested in reading more on this.
Where do you obtain all this information?
thx. Pat
Avatar universal
My Psychiatrist happens to be a standing member of the center for Psychpharmocology.
He provides me with the absolute latest studies regarding new advaces in the treatment of medication resistant people such as you and I are.

Him and his coleges have a theroy that there may be more undiscovered types of Bi-polor depression that result in a lot of patient mis-diagnosis.

I was always diagnosed as Unipolar, but this new psychiatrist had a theory that perhaps I was not as medication resistant as once thought, but rather was suffering from what is now being called Bi-Polor (NOS) as in Not Otherwise Specified.

This type of depression can often mimic Uni-polor depression because it does not include bouts of Mania or Hypo-mania as with Bi-polor 1 & 2

My P-doc said that in the next year these new forms of Bi-polor will be broken down into 3 & 4 type. There is still a lot of studies being conducted to better help diagnose if these factors may contribute to why people like us are so medication resistant. We may just be getting the wrong meds.

This new P-doc currently has me on Lamictal, Pristiq, and Lithium.
He also explained that for me to get relief we may have to go as high as 600Mgs a day on the lithium and up to 250Mgs a day on the Lamictal. Accoring to him he explained that just 150Mgs a day of Lamictal is the lowest amount possible to effect change and 300Mgs of Lithium is the lowest amout to effect change.

So these dosages are not as shocking high as many may think.
As for Lithium, it is a very old drug, but do not underestimate it's amazing ability to add more punch to the antidepressant your already taking.

Lithium is also one of the only drugs proven to reduce suicidal thoughts.

Down side of Lithium is that you have to drink lots of fluids becuase it will make you sweat like a pig and you also have to get your blood lithium levels checked every 6 months to ensure your Kidneys are dealing with the drug ok.

I think your on the right track with adding Lamictal to your antidepressant, but if your depression is still not being fully kicked, then you may want to try also adding Lithium.
978117 tn?1248305090
I have been taking some form of anti-depressant steadily for 21 years.  I am pretty much stable.  I take 20 mg. of Celexa and 300 mg of Wellbutrin XL.  This seems to be a good combination for me.  I have taken others before 1988 (when I started taking it steadily), but never for a long period of time.  It was the old ones such as Endep and Elavil and I took it for about six weeks and then slowly weaned off.  I can remember having bouts of depression since I was a young child.  I have had two severe "Post-traumatic Stress" incidents in my life that required intensive treatment to bring me out of them.  I have never been hospitalized, however.  My question is what would happen if I weaned off the medication at this point?  Would it harm me?  What happens if I stay on it the rest of my life?  the only side effect I have is weight gain, and I am starting to get that in control.
Avatar universal
I guess the only way to know for sure is to try. I might add one good possability (others may disagree) but maybe your depression is not that severe to begin with. There is a rating scale that measures a persons level of depression.

Mine happens to be at the extreem high end and very cronic. It's also nearly impossible to treat and I must take massive amounts of medication to produce theraputic response.

Then you have Moderate depression. These sufferers also need medication, but there symptoms are a bit less severe.

Then you have Mild Depression. It can still be cronic, but it's not "OMG put me in the hospital depression!" These sufferers can sometimes get by without medication,but many times choose to use a low dosage antidepressant.

Don't get me wrong, for the sufferer even Mild depression is very uncomfortable.

Maybe you fall into a milder form of depression that could be controled without meds.
I have seen less severe people do it before.

I would just be careful and if you do then tell your doctor that you plan to taper off.
I tried one time to taper off my meds and I put myself in the Psych ward for 3 weeks.
Then again your probably not as screwed up as I am.

Good luck, just be careful and watch for warning signs.
Avatar universal
It least a test that show all the amino acid levels for the building block of Serotonin. If any of the building blocks is low you are in trouble for low serotonin....I took the test and showed many low levels of important amino acids...I have OCD Pure O.........

Avatar universal
I also agree it's not entirely the amount of serotonin that effects mental illness. In fact we do not know all the actions of SSRIs. We do know this. tryptophan (amino acid) converts to 5-Hydroxytryptophan (amino acid) which converts to serotonin. Whats this mean? I know there has been a study of people with Celiac Disease and mental illness. With Celiac Disease you cant absorb vital nutrients or very little. Without basic vitamins minerals you can't assimilate amino acids which are vital for brain function.This has an effect of not only serotonin but also other mood altering compounds as well.

Some people have said taking 5-HTP alone will help with depression and or anxiety. It sounds good in theory but if you don't have other vitamins and other organic compounds you won't be able to metabolize it into serotonin. You could make things worse by have 5-HTP compete for room  cross over the blood brain barrier. You could block other amino acids and compounds from from crossing the bridge that are just as important for anxiety and depression.  

In fact if you are low in those amino acids from nutrition and or autoimmune or a bad gene, than synthetic drugs will only work with the little amount of serotonin you have...Its like fighting a fire with a small bucket of water,and refilling the bucket with the water you just used. Synthetic drugs do not cure, they only help. I am not saying they are bad.

Avatar universal
I see that most of people here are med oriented. As far as I know if you rely only on meds you not gonna be ever cured, you will always fear that when you stop taking them it will hit you back. This is psychological game played by drug industry whihc is worth $12 billion a year. Do you think that they just gonna stop drugging people, not gonna happen it is grate businesses. You just have to remember that when taking antidepressants the goal is to one day get off of them completely. There are natural ways of boosting neurotransmitters, but it is much slower then drugs and requires more effort. Also ADs are effective in 50-60% and side effects can be worst then original symptoms. In addition taking them is like playing Russian roulette, you never know what gonna happen next.
Avatar universal
Yeah, I've been on meds for darn near ten years and I am sick of it. Not that ppl should feel lesser if they are on meds - I just think meds should be used as a tool to help one deal with the problems that cause the depression, so that they can learn to deal with it naturally.

I am at the point where I want off the meds. I am ready to try dealing with my problem naturally - with regular therapy, if needed. I feel "drugged" all the time, disoriented, malcontent, my memory is shot. I want to try. Try hard.
Avatar universal
Apart from exercise what other treatments or methods do you know of - or have tried?
I have a bipolar 2 friend who is a psychiatric nurse, and he swears by "true hope" which he has been taking and has been off his meds for about 4 years. I like this idea of providing the nutrients that science has proven our brain needs to produce serotonin and other stuff that helps the receptors in the brain.

710547 tn?1295446030
Hi, I came across this thread researching Serotonin levels and how to measure them and how to raise them.  I have very low levels as per a blood test.  The serum blood test is, I believe, as mentioned, measured indirectly.  The doctors and psychiatrists I've spoken with don't seem to have any answers to any of my questions, but it doesn't surprise me.  They usually aren't the best at pharmacological issues.

Serotonin is found in the pineal gland, the lining of the GI tract, the platelets, and the brain.  It cannot cross the blood-brain barrier as serotonin - only as its precursor tryptophan.  Raising levels of tryptophan isn't a very straight forward, simple process either.  After all my research up til now, I think going the "natural way" is probably the best.  I don't mean not taking meds at all - I take many - due to having multiple medical conditions.  I have MS, Systemic Sclerosis, Interstitial Cystitis, Osteoporosis, Hypothyroid, Lung problems, Gastroparesis, Scleroderma Esophagus, and on and on.  Doctors don't know what to do at this point to help me.

The things I've read so far - to raise serotonin levels - are 1. Getting sunlight - especially morning sun, 2. exercise, 3. diet rich in complex carbs and protein - salmon, turkey, walnuts, etc. (you can find lists) 4. meditation - prayer - whatever you can do to think about positive pleasant thoughts.  Serotonin greatly effects our sleep cycle, which of course greatly effects mood.

I had planned to try 5-HTP until I discovered all the possible repercussions.  I've learned the hard way that meds cause many many side effects, and as much as we at times need them - they can create havoc.  Another problem is that since we don't know how to dose these supplements nor do we know how to keep a close eye on levels, serotonin syndrome could develop (too much serotonin), which can really be damaging.  COMPLICATED MESS!
Avatar universal
I have been on prozac then effexor and over the last 2yrs switched to celexa for depression. Have recently as 2/2009 lost my husband of 19yrs and in April 2010 decided to try and get off meds... Working out/exercising 5days a week, tanning, church/praying and reading good books for grieving and letting go. But I have been a weepy a lot and snappy bit*hy and donot like it, trying to change on my own, with the help of weekly therapist sessions. I would love to not take the meds, feel like it may be my only way to maintain. Need other ways to help during this transition time... any and all suggestions accepted. thanks
Avatar universal
L-Tryptophan is an essential amino acid and the precursor to serotonin. In North America you should take L-Tryptophan rather than 5-HTP to avoid high and potentially dangerous levels of serotonin in the blood (all to do with passage through the blood brain barrier).

There are many pathways in the metabolism of L-Tryptophan, and each step in a pathway is controlled by an enzyme. These enzymes are the product of your individual genetic expression and can vary greatly from one person to another. Unlike digestive enzymes, though, you cannot simply take cellular enzymes in a capsule. Furthermore, cellular enzymes cannot work alone. Enzymes are as useless as a car without wheels if they lack critical coenzymes and cofactors that make them run. Coenzymes typically are the enzymatic-forms of vitamins, such as pyridoxal 5-phosphate (the true form of vitamin B6), but sometimes coenzymes are biochemicals few people have even heard of. Yet, they are essential to life.

For an informative article, check out this link:


The following is a link to a commercial site but I include it if you need a source for L-Tryptophan (I use them):


BTW, there is no correlation between levels of serotonin in your blood and in your brain. What is known is that too high a level in your blood can be dangerous to your health.
Avatar universal
Consider taking
L-Tryptophan to create serotonin for snappy, etc.,
Melatonin for sleep and, last,
Tyrosine for your weepy moods(Tyrosine is the precursor of three most essential Neurotransmitters during stressful conditions, and they are Dopamine, Epinephrine and Nor Epinephrine. These are the basis of elevating mood and concentration.)
Whilst your pineal gland needs serotonin with which to create melatonin, research suggests taking both serotonin and melatonin is helpful when you have depression, moods, trouble sleeping, etc.
I have been taking L-Tryptophan for some time and recently added melatonin and believe it has made a difference with regards to sleep and how I feel.
BTW, there is research that indicates a link between low levels of serotonin and migraine headaches. Three years ago, my 17 year old son started taking one (1) L-Tryptophan tablet every Sunday and has not had a migraine since. Prior to that he had at least one severe headache/migraine a week.
Avatar universal
Thank you, I will look at the info  you suggested and talk to my doc's... what you stated makes sense. WOW! I must be having a good day.
ANd will suggest to cousin who is having migranes- Again Thank you.
Avatar universal
I have been off lexapro for about 1 month, after having been on it for about 12 years. I don't really have any specific reason why I chose to go off except that I just didn't like the thought of being on it for the rest of my life, and I thought it was keeping me from feeling "real"... It has been a real struggle for me... I am very sad and irritable and wonder if I should just go back to 20mg of lexapro...
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