Inflammation tied to lower cognitive functioning before electroconvulsive therapy
Inflammatory processes were linked to lower cognitive functioning in older patients with depression before electroconvulsive therapy, with further dysfunction during and after therapy, according to a Journal of Clinical Psychiatry study.
“Electroconvulsive therapy [ECT] is a very effective treatment for depression, especially in older patients,” Angela Carlier, MD, of the Pro Persona Mental Health Institute, The Netherlands, told Healio Psychiatry. “The cognitive side effects are transient; however, the pathophysiological mechanism behind these side effects remains unclear. We wanted to examine whether inflammatory processes are involved.”
Between 2011 and 2013, Carlier and colleagues prospectively evaluated cognitive functioning among 97 patients with severe unipolar depression aged older than 55 years using the Mini-Mental State Examination (MMSE) 1 week before, weekly during and 1 week after ECT. They assessed depression, as well as the inflammatory biomarkers, C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-a (TNF-a).
The researchers excluded patients with previous diagnosis of major neurologic illness and missing serum cytokine or CRP data.
Before, during and after ECT, higher TNF-a was associated with lower cognitive function (beta = 1.05; 95% CI, 2.04 to 0.06). Higher IL-6 and TNF-a were significantly associated with lower cognitive function from baseline to assessment during ECT.
At week 4 of ECT, MMSE score decreased in patients with lower TNF-a; at 7 weeks, MMSE scores were lower in patients with higher IL-10 and TNF-a.
Following ECT, mean MMSE score increased to 26.2 from 24.1 at baseline. Higher baseline CRP and higher IL-6 were significantly associated with lower MMSE after therapy.
“Some, but not all, inflammatory markers were associated with lower cognitive functioning,” Carlier said. “What was surprising was that this association was found before the start of ECT, suggesting that inflammatory processes may be involved with lower cognitive functioning in depression in general.”
Limitations included test-retest effects, ceiling effect, inability to evaluate specific cognitive domains and non-sensitivity to small changes, Carlier and colleagues wrote.
Future studies on the association of depression, inflammation and cognitive function and efficacy of anti-inflammatory treatment during ECT are needed, according to the researchers.