Is Depression in Your Blood? - Chromatography Explores

Depression is a horrible mental condition. To use its Sunday name - major depressive disorder (MDD) - MDD is a condition that many people have heard about - it is estimated that up to 10% of the population will suffer from it. The symptoms can range from low mood for a few weeks to years of suffering, shut away from society. It can even be fatal, with around 5% of adults who suffer from depression committing suicide.

The causes of depression are not understood properly, with genetics, brain chemistry and a severe trauma being among the commonly suggested causes. It can happen at any age, but people in their 20s and 30s appear most susceptible. Modern theories suggest that reduced serotonin levels are a common factor in the brains of people suffering from depression - hence the treatment with selective serotonin reuptake inhibitors that stop serotonin being reabsorbed in the brain.

Glutamate - excitatory neurotransmitter

Neurotransmitters act in one of two ways - excitatory or inhibitory. Excitatory neurotransmitters make a target neuron ‘fire’ an action potential and continue the signal to surrounding cells. Whereas inhibitory neurotransmitters make a target neuron less likely to fire an action potential. This isn’t clear cut, and context is needed to fully understand a neurotransmitters role. But one of the most abundant excitatory neurotransmitters in the brain is the amino acid glutamate - and some theories think that it could be glutamate that plays a greater role in depression than currently thought.

Glutamate and depression

There is evidence that glutamate signalling pathways could be involved in the pathophysiology of MDD. If the pathway is disrupted, then the cells in the brain may not function properly. Excessive glutamate release in the brain can also lead to a condition known as excitotoxicity, which is where nerve cells are damaged or killed due to excessive stimulation by neurotransmitters. Excitotoxicity is also thought to be a potential cause for mental health problems. Glutamate has a key role in brain development and function - so its regulation is essential.

A paper published in the journal Neuropsychiatric Disease and Treatment - Elevated peripheral blood glutamate levels in major depressive disorder - reports on a meta-analysis carried out to check the link between glutamate and depression. Glutamate levels in blood can be measured using liquid chromatography, a technique used to measure other chemicals implicated in brain behaviour as discussed in the article, Identification of an Unknown Constituent in Hemp-Derived Extract Using Reversed-Phase Orthogonal Methodology.

As the team report: Our findings suggest that changes in glutamate levels may be implicated in MDD and provide further support for the glutamatergic dysfunction hypothesis of MDD. This could mean that we have to look elsewhere for the causes of depression, and maybe develop new drugs that can help regulate the glutamate levels in the brain.