Dr. Katie Stewart

Dr. Katie Stewart is a registered clinical psychologist in Ontario with expertise in the treatment of anxiety disorders, obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD), perfectionism, and depression. She provides evidence-based assessment and therapy to help clients reduce distress, understand themselves better, strengthen coping skills, and live more meaningful lives. Her approach is collaborative, goal-oriented, and values-based, emphasizing an individualized plan that aligns with each client’s needs and priorities.

Dr. Stewart’s work is guided by the belief that therapy should empower people to face life’s challenges with courage, clarity, and self-compassion. She loves watching her clients learn to confront their fears and do things they never thought they could do. Her goal is to foster self-confidence in the ability to tolerate the unavoidable uncertainties and stressors of life, while working to reduce unnecessary suffering and emotional pain.

Professional Background and Qualifications

Dr. Stewart earned her Ph.D. in Clinical Psychology from Toronto Metropolitan University (formerly Ryerson University), where her research focused on cognitive mechanisms of worry and intolerance of uncertainty. She completed clinical training at several of Ontario’s leading hospitals, including St. Michael’s Hospital, St. Joseph’s Healthcare Hamilton, and Sunnybrook Hospital.

Dr. Stewart currently holds multiple clinical and leadership roles. She is a Clinical Consultant with the Ontario Structured Psychotherapy Program at Ontario Shores Centre for Mental Health Sciences, where she provides consultation, training, and program development related to the treatment of anxiety, mood, trauma, and obsessive-compulsive concerns. 

She is passionately involved in working with the first responder/public safety community and has been an invited speaker at Badge of Life conferences, most recently focusing on guiding leadership to best support their frontline workers. 

Dr. Stewart is a Qualified Provider of Cognitive Processing Therapy (CPT) and has completed advanced training in Prolonged Exposure Therapy. She is committed to inclusive, culturally competent care and welcomes clients from all walks of life.

Dr. Stewart is a Board Member and the President Elect of the Ontario Psychological Association. She is also an active researcher, serving as the Clinical Training Co-Lead on a CIHR-funded clinical trial at St. Michael’s Hospital studying Cognitive Processing Therapy combined with psilocybin-assisted treatment for PTSD.

She has authored multiple peer-reviewed publications on anxiety, worry, emotion regulation, and evidence-based treatments, and she frequently presents at national and international conferences, including the Association for Behavioral and Cognitive Therapies (ABCT), Canadian Psychological Association (CPA), and the International Society for Traumatic Stress Studies (ISTSS).

Selected Publications

• Schaffer, J., Stewart, K. E, Ovanessian, M., Zheng, S., & Koerner, N. (2025). Shame aversion contributes to worry above aversion to other emotions in generalized anxiety disorder. International Journal of Cognitive Behavioral Therapy, 18(1).
• Malivoire, B. K., Stewart, K. E., Cameron, D., Rowa, K., & McCabe, R. E. (2024). Effectiveness and predictors of group cognitive behaviour therapy outcome for generalized anxiety disorder in an out-patient hospital setting. Behaviour and Cognitive Psychotherapy, 52(4), 440-455.
• Henderson, L.C., Stewart, K.E., Koerner, N., Rowa, K., McCabe, R.E., & Antony, M.M. (2022).The relationship between religiosity, spirituality, and obsessive-compulsive disorder-related symptoms in clinical and nonclinical samples. Psychology of Religion and Spirituality, 14(2), 208-221.
• Stewart, K. E., & Antony, M. M. (2022). Exposure for multiple anxiety disorders. In J. Smits, J. Jacquart, J. Abramowitz, & J. Arch (Eds.), Clinical guide to exposure therapy- Beyond phobias. Springer.
• Cupid, J., Stewart, K. E., Sumantry, D., & Koerner, N. (2021). Feeling safe: An investigation of excessive worriers’ detection and use of safety cues presented in uncertain everyday scenarios. Behaviour Research and Therapy, 147, 103973.
• Stewart, K. E., Sumantry, D., & Malivoire, B. (2020). Family and couple integrated cognitive behavioural therapy for adults with obsessive-compulsive disorder: A meta-analysis. Journal of Affective Disorders, 277, 159-168.