Which came first, the high glucose or the depression?

There are reams of references in the National Library of Medicine database reporting on what happens to blood glucose in the presence of numerous psychotropic medications. It seems that group wisdom points to the repeated finding that glucose can elevate as a result of some medication options.

Now, a group of researchers has shown that glucose changes can actually change how serotonin receptors work.

In the short term (several hours), elevated glucose decreased serotonin uptake.

In the long term (4 to 6 months), elevated glucose increased serotonin uptake.

It wasn't the attraction of the receptor to the molecule that was the problem. It was the activity of the receptor itself.

Which has me wondering a few things.

1. What is the point of giving a medication that increases the number of serotonin molecules when the limiting issue is about a completely different issue--whether or not the serotonin receptors are actively engaging with those molecules? You can put a million molecules out there, but if they can't get the attention of the receptors, seems like a moot strategy.

2. Seems like a setup for a vicious cycle--meds, higher glucose, more depression, more meds...yadayadayada. That is, when doctors don't let a medication sit and "brew" in the system long enough to see how it's really going to work. That's not what I see. Physicians often have very short attention spans and tend to stop one medication and start another one, frantically looking for the "fix". Looks like you truly have to let a med settle in for 4 to 6 months before making any decisions about its effectiveness.

3. Maybe we should be looking more closely at this interaction and trying to understand exactly why glucose metabolism and serotonin transport are so closely related? Nature made our brains that way for a reason. Sometimes throwing a medication at the problem we can see keeps us from seeing and understanding the problem we need to see.

I still think anyone who is diagnosed with depression should automatically get a referral to a mental health-specializing dietitian. There are a myriad of things that can be added to a treatment plan that can often keep this from even being something we have to discuss.

Gonçalves P, Araújo JR, Martel F. The effect of high glucose on SERT, the human plasmalemmal serotonin transporter. Nutr Neurosci. 2008 Dec;11(6):244-50.