Transcranial Photobiomodulation in Anxiety Disorders

The investigators will conduct two studies: one examining the efficacy of transcranial photobiomodulation as a standalone treatment to alleviate sub-clinical anxiety symptoms and another evaluating the role of transcranial photobiomodulation as an adjunct to a form of cognitive behavioral therapy in anxiety treatment. The investigators will recruit individuals with sub-clinical anxiety and use attention bias assessment (ABA) to assess levels of anxiety, and then use attention bias modification (ABM) to reduce levels of anxiety. Brain activity will be monitored using functional near-infrared spectroscopy (fNIRS). An online prescreen questionnaire will be used to determine participant eligibility. No medical records are accessed/obtained for verifying inclusion/exclusion criteria. Informed consent is obtained during the first in-person visit. Participants fill out questionnaires to assess their medical history and anxiety/depression symptoms. The participants then participate in either ABA or ABA/ABM while wearing the fNIRS headset before and after transcranial photobiomodulation treatment or sham. Both studies will comprise three in-person visits with an online follow-up a week later. In this single-blind, sham-controlled experiment, block randomization will be performed to minimize selection bias and allocation bias.