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Pitt Psychiatry investigators have recently published papers in Neuropsychopharmacology reporting findings on biomarkers for suicidal behavior, as well as on harm avoidance in individuals with obsessive-compulsive disorder.

Hair Cortisol Concentrations as a Putative Biomarker for Suicidal Behavior

Suicide is a leading cause of death for young adults in the United States, but predicting who will attempt suicide is a difficult task. This is due to a variety of factors, including the dynamic nature of suicidal ideation and intent, as well as the reliance on self-report. Thus, researchers and clinicians have emphasized the importance of identifying objective, reliable biomarkers that could be applied to suicide prediction and prevention efforts. Parallel to this suicide crisis, opioid-related mortality in young adults has increased by over 250% over two decades. Between 10 and 37% of suicides are misclassified as accidental deaths. In the absence of clear corroborating evidence of suicide (such as a suicide note) medical examiners classify overdose deaths as accidental or undetermined, potentially leading to an underestimate of deaths by suicide. Thus, identifying objective and reliable markers of suicidal thoughts and behaviors can also benefit postmortem classification of suicide versus accidental deaths.

Scientists including Lindsay Taraban, PhD (postdoctoral scholar, first author of the paper) and Nadine Melhem, PhD (Professor of Psychiatry and Clinical and Translational Science, senior author), examined hair cortisol concentrations as an objective marker of risk for suicidal behavior across the full spectrum of suicidal behavior, including death by suicide. They found that hair cortisol concentrations were significantly lower in those who died by suicide, compared with those with suicide attempts, suicidal ideation, and those with psychiatric disorders but no current history of suicidal ideation and behavior. They also found those who died by suicide to have lower hair cortisol concentrations compared to accidental deaths. 

“These findings replicate our prior results and extend them to those who died by suicide. Hair cortisol concentrations reflect HPA axis activity prior to death by suicide. Future studies are needed to determine whether this biomarker predicts future proximal risk for suicidal behavior and the mechanisms through which blunted HPA axis profile increases risk,” said Dr. Melhem.

Taraban L, Hone E, Jia-Richards M, Kelly MA, Lindsay JM, Riston S, Hutchinson Z, Walko TD, Goodfriend E, Thoma BC, Sakolsky D, Chen K, Douaihy A, Brent DA, Marsland AL, Lewis DA, Melhem NM.

Neuropsychopharmacology. 51, 1084–1090 (2026). https://doi.org/10.1038/s41386-026-02344-y 

Medial Prefrontal-Thalamic White Matter Microstructure Is Associated with Harm Avoidance in OCD: a Discovery and Transdiagnostic Replication Study

Obsessive-compulsive disorder (OCD) is characterized by intrusive thoughts and compulsive behaviors, with harm avoidance (heightened sensitivity to potential threats and excessive avoidance behaviors) and incompleteness (persistent sense of imperfection or the need for things to feel “just right”) being prominent symptoms. However, they are not exclusive to the disorder. Neuroimaging work by João Paulo Lima Santos, MD (Research Instructor in Psychiatry), and colleagues has begun to elucidate the shared neural mechanisms underlying harm avoidance and incompleteness in OCD and comparison subjects.

A recent study replicated and extended prior findings in OCD in a new, independent external sample. The team of scientists examined the relationship between fractional anisotropy in prefrontal cortex-subcortical white matter connections and symptom dimensions of harm avoidance and incompleteness in unaffected comparison subjects and clinical participants, including individuals with OCD, obsessive-compulsive personality disorder, and non-OCD psychiatric disorders. Their findings showed that higher fractional anisotropy in both the left and right connections between the caudal anterior cingulate cortex, represented as the dorsomedial prefrontal cortex and the thalamus, was associated with greater harm avoidance, while higher fractional anisotropy in the left dorsomedial prefrontal cortex-thalamus connection was also linked to higher incompleteness. 

“This work strengthens evidence for a replicable, transdiagnostic association between prefrontal cortex–thalamic connectivity and OCD core symptoms, highlighting a shared neural substrate across clinical and non-clinical populations with important implications for dimensional models of OCD psychopathology,” said Dr. Lima Santos, lead author of the study.

Lima Santos JP, Versace A, Arora M, Bertocci MA, Chase HW, Graur S, Bonar L, Maffei C, Yendiki A, Boisseau CL, Haber SN, Rasmussen SA, Phillips ML. 

Neuropsychopharmacology. (2026). https://doi.org/10.1038/s41386-026-02357-7