Brittain Mahaffey

Dr. Brittain Mahaffey (she/her) is a Licensed Clinical Psychologist, Linehan Board Certified therapist (DBT-LBC), Certified Perinatal Mental Health Counselor (PMH-C), and Assistant Professor in the Department of Psychiatry and Behavioral Health at Stony Brook University Renaissance School of Medicine.

She is the founding director of the Stony Brook Medicine Outpatient DBT Program, where she oversees a comprehensive dialectical behavior therapy program serving individuals with severe emotion dysregulation, suicidality, and self-harm. Her clinical work is rooted in evidence-based practice, with particular expertise in DBT, cognitive behavioral therapy, exposure-based treatments for OCD, and mindfulness-based interventions.

Her research program focuses on intervention development for high-risk populations. She has led the development of multiple clinical interventions — including the Disaster Worker Resiliency Training Program, the Stony Brook Health Enhancement Program, and the SMART Mom Program, a resilience training program for women with elevated pregnancy-specific stress based on the 3RP — and her work adapting DBT for transgender and gender diverse youth and autistic individuals reflects a commitment to extending evidence-based treatments to underserved populations with significant emotion dysregulation and suicidality risk. Her emerging research examines suicidality in midlife women, particularly the relationship between fluctuations in sex hormones such as estrogen during perimenopause and suicide risk — connecting her expertise in reproductive mental health with her focus on high-risk populations.

With 49 peer-reviewed publications and 5 book chapters, her research spans DBT, perinatal mental health, OCD, PTSD, and the development and validation of clinical measures. Her work has been funded by the National Institutes of Health and published in leading scientific journals including JAMA Pediatrics, Social Science & Medicine, and the Journal of Abnormal Psychology.

Dr. Mahaffey serves on the executive board of the SBU-Consortium Psychology Training Program, where she is deeply invested in training the next generation of clinical scientists. She mentors clinical interns, graduate students, and postdoctoral fellows in evidence-based treatment delivery, clinical research methodology, and the development of independent research programs.

Education & Training

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Awards & Honors