Photobiomodulation in Autism Spectrum Disorder (ASD)

Subjects may be included in the study only if they meet all of the following criteria: * Male or female participants between 9 and 59 years of age (inclusive) * Fulfills DSM-5 diagnostic criteria for autism spectrum disorder as established by the clinical diagnostic interview. * Participants with at least moderately severity of ASD symptoms as demonstrated by SRS raw score ≥ 85 and CGI-ASD severity score ≥ 4 * Participants must understand the nature of the study. If the participant is under the age of 18, the participant's parent/guardian must sign an IRB-approved informed consent form before initiation of any study procedures. Participants ages 18-59 must sign an IRB-approved informed consent form before the initiation of any study procedures. * Participants must have a level of understanding sufficient to communicate with the investigator and study coordinator, and to cooperate with all tests and examinations required by the protocol. * Participant experiencing a major psychiatric disorder will be allowed to participate in the study provided they do not meet any exclusionary criteria. * Women of child-bearing potential must use a double-barrier method for birth control (e.g. condoms with spermicide) if sexually active. * The subject is willing to participate in this study. Subjects will be excluded from the study for any of the following reasons: * Impaired intellectual capacity (clinically determined) * Participant is unable to communicate due to delay in, or total lack of, spoken language development (grossly impaired language skills) * Clinically unstable psychiatric conditions or judged to be at serious safety risk to self (suicidal risk) or others (within past 30 days). * Subjects currently (within past 30 days) experiencing significant symptoms of major psychiatric disorders as clinically determined. * Subjects with an unstable medical condition (that requires clinical attention). * Active suicidal or homicidal ideation, as determined by clinical screening. * The subject has a significant skin condition at the procedure sites (i.e., hemangioma, scleroderma, psoriasis, rash, open wound or tattoo). * The subject has an implant of any kind in the head (e.g. stent, clipped aneurysm, embolised AVM, implantable shunt - Hakim valve). * Any use of light-activated drugs (photodynamic therapy) within 14 days prior to study enrollment (in US: Visudine (verteporfin) - for age related macular degeneration; Aminolevulinic Acid- for actinic keratoses; Photofrin (porfimer sodium) - for esophageal cancer, non-small cell lung cancer; Levulan Kerastick (aminolevulinic acid HCl) - for actinic keratosis; 5-aminolevulinic acid (ALA)- for non-melanoma skin cancer) * Current treatment with a psychotropic medication on a dose that has not been stable for at least 4 weeks prior to initiating study treatment. * Investigator and his/her immediate family, defined as the investigator's spouse, parent, child, grandparent, or grandchild.