Elevated translocator protein binding, a marker of neuroinflammation, was associated with heightened stress-related suicidal ideation and negative mood in patients with major depressive disorder, according to a recent study. 

A cross-sectional study examined the relationship between neuroinflammation, measured via translocator protein (TSPO) binding, and stress-related suicidal ideation and mood in patients with major depressive disorder (MDD). The study, published in JAMA Psychiatry, assessed 53 adults (mean [SD] age, 29.5 [9.8] years; 69.8% female) who met DSM-5 criteria for current MDD. Exclusion criteria included schizophrenia spectrum disorders, significant physical illness, and substance intoxication. Positron emission tomography imaging using the ¹¹C-ER176 radiotracer was performed to quantify TSPO binding, with a weighted average calculated across preselected brain regions identified as regions of interest based on prior research. Additionally, 21 patients completed a 7-day ecological momentary assessment (EMA) of stress, mood, and suicidal ideation.

The primary outcome was the total distribution volume of TSPO binding, a marker of neuroinflammation. Secondary measures included clinician-rated suicidal ideation via the Beck Scale for Suicidal Ideation (BSS) and EMA-reported stress and mood. Results showed no significant differences in TSPO binding between patients with (n = 15) and without (n = 38) a history of suicide attempts (β = 0.18; 95% confidence interval [CI], −0.04 to 0.37; P = .11). However, elevated TSPO binding showed a trend-level association with greater BSS-assessed suicidal ideation severity (β = 0.19; 95% CI, −0.03 to 0.39; P = .09). Exploratory analysis indicated that patients endorsing any suicidal ideation had significantly higher TSPO binding compared to those without (β = 0.21; 95% CI, 0.01 to 0.98; P = .045).

Among the 21 EMA patients, elevated TSPO binding correlated with increased suicidal ideation (β = 0.12; SE, 0.06; 95% CI, 0.01 to 0.23; P = .03) and negative affect (β = 0.19; SE, 0.06; 95% CI, 0.08 to 0.30; P < .001) during stress periods compared to nonstress periods. Stressors occurred in 41.2% (SD, 29.4%) of EMA epochs, and stress-related negative affect was significantly higher (β = 0.37; SE, 0.05; P < .001).

Full disclosures can be found in the published study.