Perceptual Retraining to Reduce Suicide Risk
Condition: Perceptual Olfactory Bias
MeSH terms: Suicide
Study type: Interventional

Summary: 
      The study will use a prospective design consisting of three phases. The phases are:

        1. the development of the perceptual retraining treatment (PRT),

        2. the evaluation of the treatment's feasibility and acceptability, and

        3. an assessment of its efficacy.

      During the third phase, a pilot study will be conducted in which participants will be
      randomly assigned to either PRT or a waitlist control group in order to assess efficacy.
      Diagnostic information and eligibility criteria will be assessed using the Structured
      Clinical Interview for Diagnostic and Statistical Manual (DSM) 4th ed. (SCID) and the
      Clinician Administered PTSD Scale for DSM-5 (CAPS-5).
    

Detailed description: 
      This study will use clinical interviews, self-report measures, and behavioral assessments to
      evaluate the efficacy of the PRT protocol. The study will recruit approximately 30 veterans.
      The primary inclusionary criterion will be that participants must show some evidence of
      olfactory perceptual bias toward military-relevant stimuli (e.g., burning rubber, decay,
      fuel). Investigators are not requiring current suicidal ideation as an entry criterion
      because investigators believe that a fair percentage of veterans will have some suicidal
      ideation/intent but making this an entry requirement will limit the investigators ability to
      recruit given the tight timeline for the study.

      The study will consist of the development and evaluation of a novel intervention. The
      essential feature of this intervention is the use of a gradient of triggering smells (e.g.,
      burning rubber, decay, fuel, etc.), to which participants will be systematically exposed in
      an effort to facilitate habituation to these odors. The PRT protocol will be administered
      over two 1-hour sessions. Participants will return 1 month after their final PRT protocol
      session to complete a battery of follow-up measures, as well as the CAPS-5.

      The primary outcome measures of interest are: olfactory perceptual bias (as measured by the
      olfactory bias assessment), suicidal ideation and behaviors (as measured by the Beck Suicide
      Scale and Depressive Symptom Inventory- Suicidality Subscale), and symptoms related to
      suicide, such as anxiety and trauma (as measured by the Beck Anxiety Inventory and PTSD
      Checklist for DSM-5, respectively).
    

Intervention name(s): Perceptual Retraining Treatment; Sham Neutral training
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Perceptual retraining involves the systematic presentation of diluted malodors (i.e., odors perceived as threatening). For each individual, vials on either side of a pre-determined and ideographic detection threshold will be presented. During the retraining, participants will be given feedback to shift their bias away from the malodorous target stimuli. For example, in the context of diluted solutions participants will be given the feedback that they are "correct" when a "neutral" response is given to solutions that are above the starting threshold (stronger malodor) and "incorrect" when a target is endorsed that is below the starting threshold (weaker malodor).; Control condition using systematic presentation of diluted neutral-neutral odor pairs.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment