This is a single-center, open-label,longitudinal, empirical, feasibility trial of a 12 week intervention of Sudarshan Kriya Yoga in patients with Post traumatic stress disorder.

Research participants will be men and women, 18-75 years of age, who have a confirmed diagnosis of PTSD. Recruitment will occur from the general adult ambulatory mental health clinics as well as the geriatric mental health program in London.

Potential participants will be screened as per inclusion and exclusion criteria by trained research staff. These patients will already have a clinically diagnosed PTSD by a psychiatrist and any other co-morbid diagnoses would have been previously confirmed by the physician. However, for research purposes a diagnosis of PTSD will be confirmed through a structured clinical interview specifically the MINI (Mini International neuropsychiatric Interview) and the Clinician-administered PTSD Scale for DSM5- past month version (CAPS5). CAPS5 will also be used to rule out exclusion criteria of severe depersonalization and derealization. The scales will be administered by a trained research staff and confirmed by a psychiatrist. The MINI will also be used to assess for presence of current suicidality. If the total score on Questions C1 and C2 is more than 5 then this will be reported to the PI who will further assess the patient for safety and risk assessment. If the participant is above the age of 65 years of age they will also be asked to complete a cognitive screening test (Mini Mental State Examination, MMSE) to ensure they are not suffering from any significant cognitive impairment

A 12-week intervention of Sudarshan Kriya Yoga will be conducted, as per the details provided below. The SKY PTSD program is a mind-body resilience building program which has been specifically developed for persons with PTSD by the investigators collaborating not for profit organisation, Art of Living Foundation. The investigators wish to assess the feasibility of this intervention in the investigators routine trauma clinic at LHSC. The prescribed program of SKY includes specific breathing exercises, interactive discussions, journaling, yoga and guided meditations. It is supposed that the workshop builds a framework for resilience and empowerment, and develops self-awareness, connectedness and community, and a positive outlook. This minimally invasive treatment is not routinely performed as part of standard of care and is being applied in the study population for research purposes only. In addition to using feasibility measures, the investigators will use well-established clinical scales to assess symptoms of PSTD as well as comorbid depression, anxiety, quality of life as well as physiological measurements of the heart. These specifically include heart rate variability (HRV) and blood pressure measured at baseline (week 0), week 12 and week 24. Additionally, the investigators shall collect blood samples to measure possible changes in blood inflammatory markers at these three intervals of the study as described below.

Sudarshan Kriya Yoga (SKY): Participants will continue to receive their treatment as usual, including pharmacotherapy and/or psychotherapy. Following the initial clinical screening measurements, participants will undergo a 12-week training course conducted by certified instructors from the Art of Living Foundation who will be supervised by one of the study co-investigators (RN). There will be two instructors for this study (one male Spenser Delisle and one female Hiteshini Jugessur) for the initial 6 day course; both are certified as Art of Living instructors of SKY, in addition to being certified to work with traumatized populations. They have had experience of teaching more than 2000 people in multiple settings. Additional certified instructors may conduct follow up sessions. There will always be an overlap between the existing instructor and a replacement instructor, to ensure comfort of study participants. SKY training will take place in group-format (group sizes of 8-15 participants) in an appropriately sized and accessible community hall in London, Ontario. Given that men and women tend to have different sources of trauma, separate groups will be held for each gender. This is in accordance with current practices used in the Trauma Program at LHSC. While the investigators do not anticipate gender differences, the investigators have decided to stratify this study by gender to allow participants in these groups to feel more safe and comfortable, which is key to maximizing benefits of the course. SKY training involves attending a week-long (6 days) course that teaches the basic principles of SKY over 2.5-3 hour daily sessions. This will be followed by once weekly follow up sessions (90 min/wk) for 3 weeks and then bimonthly sessions (every 2 weeks) for the next 8 weeks. In addition, participants will be asked to practice SKY at home daily (25 min/day) throughout the duration of the study period and log practice frequency and any other noteworthy observations in a log sheet that will be provided to them (please see attached log sheet). Nutritional snacks will be provided during the 6 session SKY training course. Information regarding demographic data, past psychiatric history, current ongoing psychological interventions, current medications, smoking and substance use status and any comorbid medical illnesses will be collected at baseline. Any change in status of ongoing psychological interventions, medications, smoking, alcohol and substance use, medical illnesses will be noted at each assessment visit in addition to hospitalizations or ER visits. This information is important to control for confounding factors as well as for risk assessment. The weight and height of patients will be measured at baseline and weight will be measured at each assessment visit to monitor for any effect of SKY yoga on weight (positive or negative). The information will be asked from the patient and/ or collected from the clinical charts if patient is distressed about giving the information, particularly past psychiatric history including trauma. Any adverse effects related to SKY will be monitored using a structured questionnaire, at each assessment visit (week 4, 8, 12 and 24).