https://www.theguardian.com/society/2022/nov/05/study-finds-first-evidence-of-link-between-low-serotonin-levels-and-depression

Or is it?

Antidepressant medications are usually SSRIs. Thus, it is commonly assumed that depression must be a serotonin deficiency. However, first time trials for SSRIs are only effective for about 30-50% of the depressed population. So is depression not a serotonin deficiency? Or is it? A meta-analytic study earlier this summer made huge waves on social media, when its’ researchers uncovered that there was no causal link between serotonin and depression. Low serotonin may not in fact, be the cause but perhaps the effect, for a certain cohort of the population with genetic vulnerabilities in this mood-modulating neurotransmitter system. The study even found that in many cases those with higher serotonin levels seemed to have depression- this is not unlikely as any type of excess neurotransmitter excitation in the presence of chronic stress, can lead to depression. That meta-analytic study however as well as the study below which did find a link between low serotonin neurotransmission and depression, did not account for chemical imbalances in any other brain system, hence, the conflating results. We, at Personalized Prescribing Inc. know that the two findings are not mutually exclusive, but can both be true, depending on which brain systems are most genetically vulnerable in a given individual. SSRIs’ end goal is to stimulate neurogenesis-improving cell signalling and regeneration, and maintaining brain volume integrity which may be compromised as a result of stress. Stimulating the serotonin system is one way to achieve this if one has a serotonin deficiency, however, for those without major serotonergic vulnerabilities experiencing depression, there are other systems that can be targeted by medication to achieve the same outcome, for individuals with different dominant vulnerabilities. Depression has many nature and nurture causal factors, and there is no one size fits all approach to treatment. A genetic test prior to or after one failed treatment can help narrow done which of your systems might best respond to treatment should you experience major depressive disorder. 

By Sandra Hanna
Lead Pharmacist
Personalized Prescribing Inc.