Inclusion Criteria:  diagnosed with PTSD according to DSM-IV or DSM-5 criteria current treatment at the outpatient facilities of Lev HaSharon Netanya Adult Clin age between 20 and 60 years PTSD diagnosis at least one month prior to study inclusion no present-day re-exposure to the traumatic event any psychotropic drug therapy that is being administered must be at a fixed dose for at least one month prior to the study conductance  Exclusion Criteria:  comorbid major psychiatric disorder, e.g. psychotic disorder, unipolar or bipolar disorder, borderline personality disorder, or active suicidal ideation, ADHD diagnosis, significant or severe systematic disease that limits normal activity, e.g. autoimmune disease, AIDS or renal failure, cardiovascular disease, e.g. hypertension, atrioventricular (AV) block, bradycardia, or conduction disorder, severe disease that is a threat to life, e.g. acute myocardial infarction, respiratory failure, or cancer, nervous system impairment, e.g. multiple sclerosis, Alzheimer's disease, Parkinson's disease, epilepsy, or stroke, previous or current severe traumatic brain injury, glaucoma, impaired hearing, pregnancy or breastfeeding during study inclusion, active substance dependency including regular use of medical cannabis, use of steroid medication in the two months prior to study conductance, use of medication that may affect the function of the central nervous system, failure to complete all research steps