The overarching goal of this pilot study is to conduct the first research examining real-time associations between stress-mediating biochemical markers and suicidal thoughts and behaviors (STBs) in daily life. There is a critical need to improve prediction of which individuals are at greatest risk for suicide, and when suicidal crises will occur. Multi-method intensive longitudinal approaches to study how STB risk unfolds in real-time could improve timely and personalized interventions. Importantly, many individuals who experience STBs exhibit impaired biological responses to stress. Research suggests STBs are associated with abnormal levels of stress-mediating biochemical markers, including pro-inflammatory cytokines, cortisol, and glucose. Like STBs, these stress-mediating biochemical markers fluctuate rapidly in response to daily stressors, indicating they may impact momentary risk for STBs. However, little to no previous research has studied how real-time changes in stress-mediating biochemical markers relate to STBs in daily life.
We propose to add continuous biochemical marker measurement to an ongoing multi-method R01 study on proximal risk factors for suicide (R01MH128248). We will implement an innovative wearable device, the Sweatsenser, that continuously and noninvasively measures biochemical markers in passively expressed sweat. Adult psychiatric inpatients with recent suicidal behavior (N=24) will complete an intensive longitudinal protocol for four weeks after psychiatric hospitalization. Data collection will include (1) continuous measurement of four stress-mediating biochemical markers via the Sweatsenser: Interleukin-6 (pro-inflammatory cytokine), Tumor Necrosis Factor-a (pro-inflammatory cytokine), cortisol (stress hormone), and glucose (blood sugar); and (2) simultaneous ecological momentary assessment of self-reported STBs and proximal risk factors for STBs (stressful events, sleep disturbance, substance use, and affective-cognitive factors). STBs are also measured retrospectively at follow-up. Our first aim is to establish the feasibility and acceptability of using sweat-sensing wearable devices to continuously measure biochemical markers in a clinical sample with high suicide risk. Our second aim is to examine temporal associations between the biochemical markers and STBs. We hypothesize that momentary increases in Interleukin-6, Tumor Necrosis Factor-a, cortisol, and glucose will increase risk for subsequent suicidal ideation during the 4-week post-hospitalization period. Additionally, we hypothesize that higher overall levels and greater variability of each biochemical marker will associate with suicidal behavior at 6-month follow-up. Our exploratory third aim is to examine how potential indirect associations between the biochemical markers and other proximal risk factors influence suicidal ideation during the four weeks after hospitalization. We will leverage idiographic intensive longitudinal analyses to achieve these aims in the pilot sample.
Establishing method feasibility and identifying real-time associations between stress-mediating biochemical markers and STBs could lead to significant advancements in personalized technologically-based interventions for suicide. Results from this pilot study would lay the groundwork for future large-scale research that uses continuous measurement of biochemical markers to (a) improve real-time risk detection of STBs and (b) inform interventions that target modifiable biological risk factors for suicide.
