Inflammatory markers in ECT: Not Yet A Coherent Story

 Out on PubMed, from researchers in The Lowcountries, is this paper:

The pattern of inflammatory markers during electroconvulsive therapy in older depressed patients.

Carlier A, Rhebergen D, Schilder F, Bouckaert F, Sienaert P, Veerhuis R, Hoogendoorn AW, Eikelenboom P, Stek ML, Dols A, van Exel E.World J Biol Psychiatry. 2021 Apr 6:1-24. doi: 10.1080/15622975.2021.1907718. Online ahead of print.PMID: 33821774

The abstract is copied below:

Objectives: An association is found between changes in cytokine levels and antidepressant treatment outcome. Also, a proinflammatory profile is associated with a favourable electroconvulsive therapy (ECT) outcome. This paper investigates the pattern of inflammatory markers during a course of ECT in older depressed patients and whether this pattern is associated with ECT outcome. We hypothesized that ECT has an anti-inflammatory effect.
Methods: The pattern of CRP, IL-6, IL-10, and TNF-α during a course of ECT was examined using longitudinal mixed model analyses. Serum samples were collected in 99 older depressed patients (mean age: 72.8 ± 8.3 years, MADRS score 33.8 ± 9.0).
Results: After Bonferroni correction, there were no statistically significant alterations in levels of inflammatory markers during and after ECT. Effect sizes (Cohen's d) were -0.29 for CRP, -0.13 for IL-6, -0.06 for IL-10 and -0.07 for TNF-α. Changes in CRP or cytokine levels did not differ between remitters and non-remitters. Median baseline levels of CRP were significantly higher in remitters.
Conclusions: A small to medium effect size towards decreased CRP and IL-6 levels was observed. An anti-inflammatory effect of ECT could not be confirmed. However, the findings may suggest that patients with an inflammatory profile benefit more from ECT than other patients. Further studies are needed to confirm these findings.

Keywords: C-reactive protein; Depression; Electroconvulsive therapy; Geriatric; Neuroinflammation.

and from the text:

In conclusion, in this relatively large sample of older depressed patients receiving ECT, a small to medium effect size towards decreased CRP and IL-6 levels after a course of ECT was found. Patients who remit after ECT have similar patterns of inflammatory markers during ECT as patients who do not remit, albeit remitters had higher levels of baseline CRP. With the present findings, an anti-inflammatory effect of ECT could not be confirmed.

Once again, our colleagues from Belgium and The Netherlands have mined the data from the MODECT study. The inflammation-depression story, and the sub-plot within ECT, continues to be tantalizing but not definitive. This is largely a negative study, but the correlation between higher baseline CRP and remission is interesting.

Researchers will undoubtedly pursue this line of research; it seems likely that with increased sample sizes and refined methodology, the connection between inflammatory markers, depression, and ECT will be understood.

For followers of this literature, this high-quality paper is worth a full read, ~15 minutes.