Effects of Low-Level Laser Stimulation With and Without Fear Extinction Training

Preliminary research with non-human animals suggests that LLLT (i.e., ultra low doses of
transcranial infrared light) can enhance the retention of fear extinction learning by up
regulating neuronal metabolic activity when applied to the ventromedial prefrontal cortex
(vmPFC). Furthermore, evidence from a previous uncontrolled trial with humans suggests that
LLLT (outside the context of extinction training) can lead to a significant decrease in
symptoms of depression and anxiety when applied to the right and left dorsolateral prefrontal
cortices (dlPFC). The first aim of this study is to test whether LLLT can boost fear
reduction after extinction training in humans. A second aim of this study is to investigate
the efficacy of LLLT as a stand-alone anxiolytic intervention in a randomized controlled
trial.

Individuals between the ages of 18-65 with elevated fear in any of one of four domains (e.g.,
fear of enclosed spaces, fear of contamination, fear of public speaking, or anxiety
sensitivity) are randomly assigned to one of four treatment arms (1) Extinction Training with
LLLT, (2) Extinction Training with Sham LLLT, (3) LLLT alone, or (4) Sham LLLT alone.

To determine eligibility, all participants undergo an online prescreen and a face-to-face
screening assessment. Participants who qualify for the study then complete a baseline
(pre-treatment) assessment, followed immediately by the treatment procedure and a
post-treatment assessment. Participants return to the lab an average of 14 days after
treatment to complete a follow-up assessment. Participants complete two behavioral approach
tests (in the treatment context and in the generalization context) at baseline,
post-treatment, and follow-up, and a battery of self-report questionnaires at baseline and
follow-up.

Inclusion Criteria:

1. Ages 18-65

2. Behavioral Approach Test (BAT) peak fear rating equal to or greater than 50/100 on
both BATs (i.e., treatment and generalization contexts).

Exclusion Criteria:

1. High risk for suicide as determined by a clinical assessment, which will occur if a
participant indicates that they are currently experiencing suicidal ideation on the
depression module of the Mini International Neuropsychiatric Inventory, or on item 9
of the Beck Depression Inventory.

2. Psychotropic medication taken within the past 4 weeks.

3. Currently Receiving treatment for the fear domain in question.

4. Presence of a medical condition (i.e., pregnancy, seizure disorder, respiratory
disorder, cardiovascular disease) that would contraindicate participation in one or
more treatment or assessment activities as determined by a Medical History
Questionnaire.

5. Active neurological condition (such as epilepsy or stroke) as determined by a Medical
History Questionnaire.