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

• Ages 18-65
• 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

• 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.
• Psychotropic medication taken within the past 4 weeks.
• Currently Receiving treatment for the fear domain in question.
• 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.
• Active neurological condition (such as epilepsy or stroke) as determined by a Medical History Questionnaire.