Psychophysiological Study of Pain Perception in Depressed Patients With Suicidal Risk

Aim: The first objective of this project is to test different pain mechanisms that could be involved in the increase of pain thresholds and tolerance in suicidal patients. The second objective is to test whether there's a loss of pleasantness during social touch in suicidal patients.

The main aim is to compare the efficacity of CPM between three groups of depressed patients: recent or former suicide attempters and non-attempters. The secondary aims are 1) to compare the wind-up mechanism between groups, 2) to compare the difference of excitability of Aδ and C fibers between groups, 3) to correlate these physiological results to clinical variables (emotional reactivity and emotional regulation, dissociation and body perception), and 4) to compare the pleasantness associated with social touch between groups.

Target population: 153 depressed women will be enrolled and divided into three groups. I) Women having recently attempted suicide (less than 72 hours) - II) women having a past suicide attempt (more than 72 hours) - III) Women without lifetime history of suicidal behaviour (affective control group).

Materials: The heat test stimuli are performed by a thermode (TCS II, QST Lab) which produces ramping heat pulses from 32°C to 52°C. For the conditioning stimulus (cold pressor task), participants will insert their arm (up to the elbow) in circulating cold water (8°C). Pain intensity is rated by a CoVAS (computer visual analog scale). This scale is similar to a classic visual analog scale (VAS) ranging from "no pain" to the "most intense pain tolerable". The participant has just to move a cursor, thanks to the computer mouse. The stroking is performed thanks to a Natural hair Blush Brush (No. 7, The Boots Company).

Clinical assessment: A clinical assessment will be made by a trained researcher. This assessment will evaluate psychiatric diagnosis by the DSM-V (Diagnostic and Statistical Manual of Mental Disorders), the severity of depression by the IDS-C30 (Inventory of Depressive Symptomatology), the intensity of suicidal thoughts by the CSSRS (Columbia Suicide Severity Rating Scale), and the suicidal life history by the RRRS (Risk-Rescue Rating Scale) and SIS (Suicidal Intent Scales). It will also gather information about socio-demographic variables, the number of depressed episodes, the number of psychiatric hospitalizations, the hormonal status, and the current medications. All psychotropics medications taken by the patient will be collected for the last 72 hours, as well as the dose and the date of the beginning of the treatment. The patients will also have to complete some self-report measures about the severity of their depression (BDI-II), their level of anxiety (STAI), their physical and psychological pain (EVA current and past), their childhood trauma (CTQ), their emotional state (PANAS), their difficulty in emotional regulation (DERS), their emotional reactivity (ERS), their body perception (BIS), their dissociative experiences, their borderline symptomatology (BSL-23) and the kind of non-suicidal self-injuries practiced (SHI).