Cognitive Processing And Eye-tracking Biomarkers In Patients Of Depressive Episodes With Suicide Risk

Background: Prior studies indicated that the attentional biases,as important cognitive vulnerabilities of suicide,played a key role in the development of suicide ideation and suicidal behavior.However,the psychopathological mechanism of cognitive biases in suicidality is kept unclear.The component of cognitive biases,the specific processes of information processing,the pathway between cognitive and affective vulnerabilities in leading to suicide are still need to be explored.In addition,there are still lack of objective and biological markers for suicide risk assessment in clinical practice.To fix the theoretical and practical issues mentioned above,there are three main purposes in this study: 1.To explore the cognitive biases and scan-path patterns in depressive patients with suicide risk through eye-tracking methodology;2.To test and evaluate the classic cognitive theory of suicide behavior by index of clinical and eye-tracking measurements;3.Extract the eye-tracking markers for depression symptom and suicide ideation and test the validity and reliability of these biomarkers in a longitudinal data frame from depressive individuals.Method:(1)To establish the free-viewing task,a pilot study was completed to accumulate the suicide-related stimulus.This free-viewing eye-tracking paradigm,which simultaneously presented four images with different valences(suicide-related,negative,positive,neutral),was examined in 76 suicide attempters(SA)with unipolar or bipolar depression,66 participants with depression but no history of suicide attempts(ND),and 105 healthy never-depressed control participants(HC).Both the early and later responses were collected and were compared by ANOVA and time-course analysis.(2)The structural equation model was conducted for the theory testing,integrated both self-report(e.g.suicide ideation,hopelessness,suicidal behavior)and eye-tracking measurements.(3)86 Patient-reported clinical outcome measure scales and eye-tracking testing were completed at both baseline and 12-week follow-up visit.Repeated-measure ANOVA,pairwise T-test,Pearson’s correlation,and linear regression were conducted to evaluation the stability and validity of eye-tracking biomarkers.Results:(1)SA gazed more at suicide-relevant stimuli throughout the25-sec trial compared with ND.SA and ND initially detected suicide-related stimuli faster than HC.Groups did not differ on how often they initially gazed at suicide images or how fast they disengaged away from them.The main directions of eye-tracking performance were confirmed by the sensitivity analysis.(2)The model fix indices showed that the eye-tracking measures can sufficiently indicate the attentional biases.And eye-tracking,together with self-reported observations,adequately fit an SEM consistent with Wenzel and Beck’s cognitive theory of suicide-related information processing.(3)The improvement of depression severity and suicide ideation can be indicated by eye-tracking index from a longitudinal comparison.The increasing time of dwelling towards positive information is significantly reflected the reduced depression symptom,β =-0.470,p<.001,95%CI[-0.665,-0.274].The duration of dwelling towards suicide-specific images is positively indicator for suicide ideation,β=0.464,p<.001,95%CI[0.270,0.657].These eye-tracking patterns may be potential neuro-behavioral markers for the recovery of suicide ideation and depression in MDD with suicide risk.Conclusion:1.There are suicide-specific attentional biases in depressive-episodes patients with suicide risk and this late-stage biases are more related to elaborative processing of cognitive processing.2.This study provided solid evidence for the theoretical framework of cognitive suicide model through the bio-and behavioral measurements and tested the key roles of cognitive vulnerabilities(e.g.hopelessness,suicide-biases,suicide-fixation)in the development of suicide.3.The clinical symptoms including depression severity and suicide ideation,could be sufficiently indicated by the patterns of eye-tracking in depressive patients.