Our Team

Greta Gleissner, LCSW

Greta Gleissner, LCSW (NY 083574), is a therapist who specializes in eating disorders and trauma, In 2013, Greta founded Eating Disorder Recovery Specialists (EDRS)–pioneering an in-home, on-campus, and virtual post-acute therapeutic care and recovery support model for adolescents and adults with eating disorders. EDRS utilizes over 150 recovery specialists, utilizing in-person and virtual recovery support nationwide.

Greta’s interest in eating disorders and trauma grew out of her recovery from eating disorders and complex PTSD, which provides her with both a personal and professional lens through which to support clients. Having been a professional dancer, she knew from the age of 16 if she could ever heal from her eating disorder it would be her life’s mission to help others. Shortly after graduate school at New York University, Greta published her first book, Something Spectacular: The True Story of a Rockette’s Battle with Bulimia, a raw, personal chronicle of the devastating effects bulimia had on her personal and professional life during her time as a Radio City Rockette.

In addition to founding Eating Disorder Recovery Specialists and Sanctuary, Greta maintains a small private practice on the Upper West Side and is trained in EMDR, CBT, DBT, and Motivational Interviewing.

Sarah Chipps, PsyD

Sarah Chipps, PsyD is a New York State licensed psychologist (license #020206). She received her master’s and doctorate degrees in clinical psychology from the California School of Professional Psychology in San Francisco.

Since 2008, she has had the privilege to work with people of diverse identities and histories, in a variety of settings. Prior to opening her full-time private practice, she was clinical director at Monte Nido’s residential program for women with eating disorders in Irvington, NY.

Dr. Chipps specializes in the treatment of eating disorders, substance abuse, and trauma. She is a regular presenter at conferences on topics such as ethnic diversity, the client/therapist relationship, and creativity in the treatment of eating disorders.

Her own recovery from an eating disorder and substance dependence give Sarah an inside perspective that helps her both support and challenge clients.

Jennifer Sterling, M.S, R-DMT, LCAT

Jennifer Sterling is a Registered Dance/Movement Psychotherapist, Somatic Experiencing Practitioner, and Holistic Nutritionist. Having witnessed the adverse effects of oppressive systems on Black women in her community and through her own lived experience, Jennifer has made it her mission to support BBIWOC in healing from the effects of trauma and oppression.

She is also committed to finding ways to reduce the stigma around mental illness within Black communities.

Mary Pivarunis, LMFT, SEP

Mary is a Licensed Marriage and Family Therapist who specializes in trauma, PTSD, grief and loss. She is trained in Somatic Experiencing, Attachment Focused EMDR, and Trauma Resiliency.

Mary is delighted to be back on the East coast after spending many years in California. Most recently, Mary was part of the team at Promises Malibu Vista, a nationally respected trauma-focused residential treatment center for women, in Malibu, CA. Mary served as their Trauma Therapist and developed their trauma program over the six years of its existence.

Mary also worked as Primary and Trauma Therapist at Resolutions Therapeutic Services, an outpatient program in Santa Monica, CA.  and as a Trauma Therapist at Bridges to Recovery, a residential treatment center, in Pacific Palisades, CA. In addition, Mary worked at Alta Bates Summit Medical Center’s psychiatric hospital in Berkeley, CA, for eight years, in both the inpatient and outpatient program with diverse patient populations. She served as Program Director and Main Therapist for a variety of adult and adolescent programs.

Mary is very passionate about her work in the field of trauma and the body. Her enthusiasm, optimism and infectious sense of hope have been a comfort to hundreds of clients she has worked with over the years. Combining a real curiosity, compassionate exploration and a sense of humor, Mary helps clients understand their stories and history to create a path towards healing. Mary received her Master’s degree in Counseling Psychology with a specialization in Somatic Psychology from John F. Kennedy University in Pleasant Hill, CA.

Mary maintains a private practice in New York City where she works with adults in short and long-term psychotherapy. She is licensed in both New York and California.

Elizabeth Mangum, LCSW

Elizabeth Mangum is a New York State Licensed Clinical Social Worker (#076115). She received her Bachelors of Arts in Psychology at Michigan State University and her Masters in Social Work at The University of Michigan. Since 1998, Elizabeth has had the pleasure of working with individuals, families, and couples in a wide range of settings including the NYC foster care system, domestic violence shelters, residential treatment care programs, and services for pregnant/parenting teens. Prior to opening her private practice, she founded Nurture{Bklyn}- a community space for pregnant/parenting people- in Brooklyn, NY.

Elizabeth specializes in the treatment of Perinatal Mood and Anxiety Disorders, PTSD (chronic/complex), and substance abuse. Elizabeth has completed postgraduate training in Eye Movement Desensitization Reprocessing (EMDR) Level 1&2 and at The Ackerman Institute for the Family. To support clients on their healing journey, Elizabeth uses an eclectic mix of approaches (internal family systems, mind/body centering (DBT), narrative therapy, and cognitive behavioral therapy). Elizabeth’s passion for helping others find wholeness comes from her own experiences of intergenerational trauma and the family disease of substance abuse. Elizabeth is also a retired birth/postpartum doula and since 2004 she has supported over 200 families on their fertility journey, pregnancy and birth, and the postpartum period.

Hollis Witherspoon, MA, RDT, LCAT-LP

Hollis Witherspoon, MA, RDT, LCAT-LP is a registered drama therapist/psychotherapist and adjunct professor of art. After years in the acting field, she received her Master’s degree in Drama Therapy from NYU and began working in a multi-modal creative arts group therapy practice in Brooklyn.

Hollis is a firm advocate for the role that creative expression plays in the healing process and integrates embodied expression, art-making, role identification, and improvisation into her therapy sessions. Hollis has worked with a variety of folks from different walks of life, including graduate school faculty, social workers, military veterans, and residents at eating disorder treatment centers. Clients working with Hollis can expect warmth, curiosity, and gentle, creative support as they seek acceptance and integration of their full selves.

Outside of her therapy practice, Hollis loves to collaborate on video projects, do yoga, cartoon, and take on baking projects.

Rachel Boelter, MA, RDT, LCAT-LP

Rachel Boelter, MA, RDT, LCAT-LP is a registered drama therapist, psychotherapist and artistic director. Rachel received her master’s degree from New York University in Drama Therapy and has since worked on both inpatient psychiatry units and in outpatient treatment centers. She has specialized in working with adolescents and young adults, individuals living with difference, and individuals recovering from addiction, mood disorders, anxiety, and sexual assault.

As a creative arts therapist and former musical theatre performer, Rachel often utilizes music, dance, poetry, meditation, and art in addition to drama therapy techniques in her sessions. Rachel centers her practice around the use of humor, play, relationship, honesty, compassion, and creativity.

Chelsea Williams, PsyD

Chelsea Williams recently graduated with her doctorate of psychology in clinical psychology from the California School of Professional Psychology in San Francisco.  She completed her pre-doctoral internship training at California Pacific Medical Center Psychiatric Outpatient Department.  Her specialization areas include attachment, parenting, and child development – particularly how trauma experienced during development impacts attachment patterns.

Additionally, Chelsea’s primarily relational approach is guided by evidenced-based modalities & current research, and her treatment is informed by her expertise in the area of intergenerational trauma and how the transmission of trauma impacts current functioning.

Daniela Montenegro

Daniela graduated from Rutgers University with a BS in Criminal Justice and Psychology. After college, she decided to pursue her passion for Forensic Psychology by enrolling in  John Jay School of Criminal Justice to earn her Master’s in Forensic Mental Health Counseling – a program that makes her licensed eligible after graduation.

Currently, as an extern student with the NYPD’s Psychological Evaluation Section, she has gained knowledge and skills pertinent to conducting relevant clinical interviewing and assessment; while also gaining insight into her passions and focus as a future helping professional. She plans to continue working with law enforcement and applying her experience and skills to help support and enhance mental health in our justice system.

Elizabeth Grant, LMSW

Elizabeth Grant is a licensed social worker who received her  B.S. in psychology from the University of Michigan and her graduate degree from NYU. Elizabeth has spent her career working with children, adolescents and families in a variety of clinical settings. She is trained in Trauma Focused Cognitive Behavioral therapy for children and adolescents with C-PSTD.

Elizabeth has facilitated therapeutic supervised visitation for non-custodial parents and is passionate about addressing intergenerational trauma as it relates to family separation and systematic racism within the child welfare system. Additionally, she has experience working with neurodivergent students helping to increase executive functioning skills through the use of DBT. Elizabeth has held a variety of case management roles for New York State’s Early Intervention Program. Elizabeth strives to create a safe, therapeutic holding container and always values clients as the experts of their own experience.

Millie Chatelain

Millie is a graduate of John Jay College of Criminal Justice with a Master’s degree in Forensic Mental Health Counseling. She interned in the Counseling Department at the College of Mount Saint Vincent in Riverdale, NY. In this capacity, Millie worked with BIPOC clients whose families were unaware they were seeking support for their mental health. Through this experience, she saw firsthand how fear and stigma around mental illness in BIPOC communities can affect individuals and their ability to heal. Millie understands that each client requires a different, individualized level of care. For that reason, she does not limit herself to just one modality. Although she primarily utilizes a relational approach in the therapeutic space, she is also well versed in the psychodynamic approach, cognitive-behavioral therapy (CBT) and dialectical behavior therapy (DBT). She specializes in treatment of issues regarding anxiety, depression, trauma, relationships, self esteem, and identity. Here at Sanctuary, Millie is driven by her passion for mental health and continues to advocate for de-stigmatization of mental illness.