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I'm Lauren (she, her) and I'm the founder of Grenadier Psychotherapy. I am a Clinical and Health Psychologist registered with the College of Psychologists of Ontario. I graduated with my PhD in Psychology from Toronto Metropolitan University in 2018. I completed my residency and post-doctoral work at St. Joseph's Healthcare Hamilton, with rotations at the Eating Disorder Service, the Bariatric Surgery Program, the Women's Health Concerns Clinic, and the Anxiety Treatment and Research Clinic. 

I have received extensive training in Cognitive Behavioural Therapy (CBT), self-compassion approaches, and Motivational Interviewing. I have also been trained in the use of Acceptance and Commitment Therapy, and mindfulness-based approaches. I am a certified therapist with the Canadian Association for Behavioural and Cognitive Therapies (CACBT).

In addition to private practice, I am the Regional Clinical and Training Lead for the Ontario Structured Psychotherapy (OSP) Program at Ontario Shores Centre for Mental Health Sciences. OSP is an innovative publicly-funded initiative to provide evidence-based treatment to individuals with mood and anxiety-related issues. My primary role is providing training and consultation to mental health providers in implementing CBT. My practice is anti-oppressive, LGBTQ+ affirmative, trauma-informed, and weight inclusive.


  • Certification in CBT by the Canadian Association for Behavioural and Cognitive Therapies

  • Doctorate of Philosophy (PhD) in Clinical Psychology, Toronto Metropolitan University (Toronto, ON)

  • Master of Arts (MA) in Clinical Psychology, Toronto Metropolitan University (Toronto, ON)

  • Bachelor of Arts Honours (BAH) with Distinction, Psychology, Queen's University (Kingston, ON) 

  • Residency completed at St. Joseph's Healthcare (Hamilton, ON)

  • Post-doctoral work completed at St. Joseph's Healthcare (Hamilton, ON)

  • Clinical training completed at:

    • Academic Family Health Team, St. Michael’s Hospital (Toronto, ON)

    • Eating Disorder Day Program, Toronto General Hospital (Toronto, ON)

    • Adult Outpatient Mental Health Services, Humber River Hospital (Toronto, ON)

  • Posttraumatic Stress Disorder Assessor at the Toronto General Hospital Eating Disorder Program (Toronto, ON)

  • Telephone therapist at the Toronto Western Hospital Bariatric Surgery Program (Toronto, ON)


David, L.A., Sijercic, I., Cassin, S.E. (2020) Preoperative and post-operative psychosocial interventions for bariatric surgery patients: A systematic review. Obesity Reviews, 1-23.

Macdonald, D.E., McFarlane, T.L., Dionne, M.M., David, L.A., & Olmsted, M.P. (2017) Rapid response to intensive treatment for bulimia nervosa and purging disorder: A randomized controlled trial of a CBT intervention to facilitate early behavior change. Journal of Consulting and Clinical Psychology, 85, 896-908.

David, L.A., Sockalingam, S., Wnuk, S., & Cassin, S.E. (2016). A pilot randomized controlled trial examining feasibility, acceptability, and efficacy of adapted motivational interviewing for post-operative bariatric surgery patients. Eating Behaviors, 22, 87-92.


David, L.A. & Cassin, S. E. (2018). Motivational interviewing for behavioural and lifestyle changes in severe obesity. In S. Cassin & S. Sockalingam (Eds.) Psychological care in severe obesity. Cambridge, MA: Cambridge University Press.

Atwood, M., David, L.A., & Cassin, S. E. (2017).  Cognitive behavioural therapy for bariatric surgery patients. In R. Rajendram, C. Martin, & V. R. Preedy (Eds.), Metabolism and pathophysiology of bariatric surgery: Metabolism, nutrition, procedures, outcomes and adverse effects (pp. 595-602). Cambridge, MA: Academic Press.

Taube-Schiff, M., David, L.A., Cassin, S. E. (2017).  Motivational interviewing for severe obesity.  In S. Sockalingam & R. Hawa (Eds.), Psychiatric care in severe obesity: An interdisciplinary guide to integrated care (pp. 221-231). New York, NY: Springer.


Cassin, S.E., & David, L.A. (2015).  Binge eating disorder.  In R. Cautin & S. Lilienfeld (eds.), Encyclopedia of clinical psychology. Malden, MA: Wiley-Blackwell.


Clinical and Health Psychologist, College of Psychologists of Ontario (#6612)
Regional Clinical and Training Lead, Ontario Structured Psychotherapy Program, Ontario Shores Centre for Mental Health Sciences
Member and Certified Therapist, Canadian Association for Cognitive and Behavioural Therapies
Member, Canadian Psychological Association

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