Multiple biomarkers may improve prediction of suicidal behaviour during depression treatment

Combinations of serum biomarkers relating to cortisol, total cholesterol, and folate, as well as interleukin (IL)-1β and homocysteine, help improve the predictability of suicide attempt and increased suicidal severity, respectively, among individuals being treated for depression, according to a study.

For the study, researchers looked at 14 serum biomarkers and sociodemographic/clinical characteristics, including previous suicidal attempt and present suicidal severity, in 1,094 participants without a bipolar diagnosis. All participants were receiving a 12-month outpatient pharmacotherapy program for depressive disorders.

Of the participants, 884 were followed throughout the treatment period for increased suicidal severity and fatal/nonfatal suicide attempt outcomes. Multivariable logistic regression analysis was used to estimate the individual and combined effects of serum biomarkers on these two prospective suicidal behaviour outcomes.

During the 12-month pharmacotherapy program, 155 (17.5 percent) participants showed increased suicidal severity and 38 (4.3 percent) participants had a fatal/nonfatal suicide attempt.

Increased suicidal severity showed independent associations with above-cutoff levels of cortisol, IL-1β, and homocysteine, and below-cutoff levels of total cholesterol and folate. On the other hand, fatal/nonfatal suicide attempt was independently associated with above-cutoff levels of cortisol and below-cutoff levels of total cholesterol and folate.

Combined cortisol, total cholesterol, and folate serum biomarkers predicted fatal/nonfatal suicide attempt. The same biomarkers plus IL-1β and homocysteine additionally predicted increased suicidal severity, with clear gradients robust to adjustment (p<0.001 for all).

Of note, the higher the quartile of multi-biomarker scores, the greater the probability of suicidal behaviours (p<0.001 for trend). Compared with the lowest quartile, the highest quartile of multi-biomarker scores was associated with sixfold greater odds of increased suicidal severity (odds ratio [OR], 6.20, 95 percent confidence interval [CI], 3.15–12.2) and 32-fold greater odds of fatal/nonfatal suicide attempt (OR, 32.3, 95 percent CI, 4.20–249.0).

In light of the present data, the researchers believed it reasonable to recommend that patients with depression who have unfavourable biomarkers be monitored frequently and considered for risk appraisal. A combination of blood-based, neuropsychological, and neuroimaging factors has the potential to give a better estimate of risk, given the multiple determinants of suicide, they added.