The study, however, is observational and not interventional which, according to Kaitlin Roke, Director of Scientific Communication and Outreach at GOED, the Global Organization for EPA and DHA omega-3s means the results will need to be further validated in other populations and/or within a clinical trial.
She said: “Brain health is extremely important for overall health, and it is great to see new research contributing to this topic area. Cussotto et al. rightly state that their 'investigation does not consist of an interventional study with omega‐3 PUFA (polyunsaturated fatty acid) supplementation but it represents instead an observational one' which means that these results will need to be further validated."
Sixty patients who met the criteria for major depressive disorder (MDD) were recruited to assess the link between baseline PUFA composition and changes in depressive symptoms as well as antidepressant response in a multicentre study.
MDD is characterised by a high rate of treatment resistance and omega-3 PUFAs were shown to correlate with depressive phenotype both in rodents and humans. Few studies have investigated the role of these fatty acids in antidepressant response.
Neuropsychiatric evaluations occurred at baseline and again after four and eight weeks of treatment with standard antidepressants including escitalopram, sertraline and venlafaxine. At the end of the study those who took part were stratified into responders or non-responders based on their scores using the Montgomery-Åsberg Depression Rating Scale
The tool is a ten-item diagnostic questionnaire which psychiatrists use to measure the severity of depressive episodes in patients with mood disorders. At this point, baseline PUFAs were assessed and their association with clinical response was determined.
Lower levels of the fatty acids were associated with worse baseline symptomology and baseline levels were significantly different between responders and non-responders with the responders exhibiting lower docosahexaaeonic acid (DHA), eicosapentaenoic acid (EPA) and omega-3 index and higher omega-3/omega-6 ratio than non-responders, before the start of the antidepressant treatment. DHA levels as well as the omega-3 index and omega-3/omega-6 ratio significantly predicted response to antidepressants at study endpoint.
Kaitlin added: “In this observational study, EPA and DHA omega-3 levels were measured from a blood sample at baseline. Cussotto et al. found that PUFA baseline levels predicted response to antidepressant medication among individuals with depression.
"The authors said findings like theirs may ‘enable the early identification of patients who are at high risk of non-response to standard antidepressants’. To validate these baseline predictions on antidepressant responses, an essential next step would be to analyse data from other studies in this field for similar patterns.”
The authors of the study say the results show that baseline levels of PUFAs predict later response to standard antidepressants in depressed subjects. They suggest that PUFA intake and/or metabolism represent a novel modifiable tool for the management of unresponsive depressed patients.
Kaitlin believes that if these results can be validated, using baseline EPA and DHA omega-3 levels it could be an important assessment tool to aid in personalising healthcare, which she said she hopes to see more of in the future.
“Further, understanding the diet quality and why these levels of EPA and DHA omega‐3 are low could be one step to helping patients improve their overall health.
"Adding foods or supplements with EPA and DHA and having all participants start the intervention with a similar baseline level of these fatty acids is another approach to investigating the health effects following a new medication regime.”
In the study, it is said that “published evidence on EPA and DHA supplementation as adjunctive strategies for depressed subjects is very heterogeneous to date".
This, Kaitlin notes, makes comparing studies in this field difficult, as each study uses a unique population of participants, and uses an array of different scales and measures for diagnostics and to measure changes in clinical outcomes over the course of the study.
She concludes: “Taking a step back and evaluating these populations, and the various scales used is essential to carve a path forward in this research field and for determining what is and isn’t working.”
Published online: doi:10.1001/da.23257
Low omega-3 polyunsaturated fatty acids predict reduced response to standard antidepressants in patients with major depressive order
Authors: Sofia Cussotto et al