Perceptual Retraining to Reduce Suicide Risk

A participant's ability to detect an array of threatening malodor in neutral dilution gradients will be tested at baseline and after the second and final intervention session (one week after baseline). Perceptual bias is calculated as the percentage of correct responses (i.e., yes or no to detecting the malodor) on an odor over 6 trials for each of the 8 odors, at 25% and 33% dilution (i.e., over 96 trials). Larger positive percentages indicate greater habituation to the malodor, and therefore a training effect toward reducing threat bias (i.e., a positive effect on intervention outcomes).

The Clinician Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 (CAPS-5) was administered at the baseline appointment and 1-month follow-up appointment to assess PTSD symptom severity. All 20 of the CAPS-5 items are scored 0-4 and summed to calculate a total score, which ranges from 0-80. Higher scores indicate greater PTSD symptom severity. A difference score was calculated by subtracting the CAPS-5 score at 1-month from baseline, and averaged across each condition; thus, higher (positive) change scores are indicative of increases in PTSD symptom severity, whereas lower (negative) change scores are indicative of decreases in PTSD symptom severity.

The Depressive Symptom Inventory - Suicidality Subscale (DSI-SS) was administered at the baseline appointment and 1 month follow-up appointment to assess the severity of thoughts related suicidal ideation. All four items of the DSI-SS are scored on a 0-3 scale, with total possible sum scores ranging from 0-12; higher scores indicate greater severity of suicidal ideation. For the outcome measure reported, a difference score was calculated by subtracting DSI-SS scores at 1 month from DSI-SS scores at baseline, and averaged across conditions. DSI-SS change scores of zero reflect no change from baseline to 1 month.

The Beck Suicide Scale (BSS) was administered at the baseline appointment and 1-month follow-up appointment to assess thoughts and behaviors related to suicidal ideation, desire, and attempts. The BSS comprises 21 items rated on a 0-3 scale. The first 19 items are sum scored with total possible scores ranging from 0 - 38, with higher scores indicating greater severity of suicide risk. A difference scores was calculated by subtracting the BSS score at 1 month from BSS scores at baseline. Mean change scores of 0 reflect no change in BSS scores from baseline to 1 month.

The Beck Anxiety Inventory-II (BAI) was administered at the baseline appointment and 1-month follow-up appointment to assess symptom severity associated with anxious arousal. The BAI comprises 21 items rated on a 0-3 scale, which can be sum scored to calculate total scores ranging from 0 - 63. Higher scores on the BAI are indicative of greater anxious arousal. A difference scores was calculated by subtracting the BAI score at 1 month from BAI scores at baseline; thus, higher (positive) change scores are indicative of increases in anxious arousal, whereas lower (negative) change scores are indicative of decreases in anxious arousal.