Daniel J Tieman, PsyD

Daniel J. Tieman, Psy.D., is a Clinical Psychologist and Clinical Assistant Professor in the Department of Psychiatry and Behavioral Health at the Stony Brook School of Medicine. A graduate of LIU Post’s APA-accredited dual-orientation clinical program, Dr. Tieman is uniquely trained as both a psychodynamic and cognitive behavioral clinician, allowing for a highly integrative approach to complex case formulation.

Dr. Tieman’s extensive clinical training spans high-acuity residential care, systemic family work, and outpatient, including telemedicine. He completed an APA-accredited internship at MercyFirst, where he treated youth in the child welfare system presenting with complex trauma, PTSD, and mood disorders, followed by a Post-Doctoral Fellowship at the Stony Brook University Consortium. Prior to his current faculty role, he developed a strong theoretical and clinical systemic lens at Northwestern University’s The Family Institute.

His clinical expertise includes psychodynamic therapies, third-wave cognitive behavioral therapies such as Acceptance and Commitment Therapy (ACT) and Dialectical Behavior Therapy (DBT), including Radically Open DBT (RO-DBT), as well as adolescent disruptive behaviors, relational and integrative psychotherapy, behavior analysis, and trauma-focused treatment.

Since joining the faculty at Stony Brook, Dr. Tieman has focused on delivering holistic care to a diverse range of clients across multiple clinical areas. His leadership roles include adapting and leading RO-DBT group programming and serving as the Behavioral Health Lead Liaison as an integrative care psychologist in Family Medicine. He is actively involved in supervision and teaching, providing mentorship to psychiatry residents and psychology trainees across multiple disciplines and therapeutic orientations, while co-running the CBT consultation team and teaching didactics.

Driven by a strong commitment to serving underserved populations, Dr. Tieman recently completed specialized training at Brown University through Physicians for Human Responsibility to conduct forensic asylum-focused assessments. This commitment to social justice and holistic wellness remains a central driver of his clinical practice and research interests.