Mark Sisti, PhD Director & Founder

Mark Sisti, PhD is the founder and director of NYC Cognitive Behavioral, PLLC. He is a graduate of Hofstra University, a licensed psychologist and a adjunct professor at Yeshiva— Ferkauf University, Department of Clinical Psychology. Dr. Sisti is a Diplomat, Certified Cognitive Therapist & Trainer within The Academy of Cognitive Therapy. He is also a peer-reviewed trainer in a more contemporary experiential CBT called Acceptance and Commitment Therapy (ACT).  His advanced training in cognitive therapy was under the tutelage of CBT master clinician, Robert Leahy, Ph.D., at The American Institute for Cognitive Therapy, where Dr. Sisti was formerly the Associate Director.

Dr. Sisti has extensive experience with anxiety disorders through his work at Freedom From Fear, a nationally recognized anxiety and mood disorder advocacy organization, where he was formerly the Director of Cognitive Therapy and where he also participated as a Certified Cognitive Therapist in research trials for N.Y.S. Psychiatric Institute & Columbia Presbyterian. He has also supervised doctoral interns from both Yeshiva-Ferkauf and Hofstra Universities and is a volunteer adjunct clinical supervisor for Yeshiva University Graduate School of Psychology. He trains various mental health experts and professionals in CBT, mindfulness based CBTs, such as ACT, and  has presented trainings and symposia for the American Psychiatric Association, the American Psychological Association, Association for Contextual Behavior Therapy and Suffolk County Psych Assoc.  He has also given numerous seminars and trainings on ACT and other mindfulness based CBTs. Dr. Sisti is also a published author on cognitive therapy, mindfulness, ACT, and Compassion Based Therapy, and Functional Analytic Therapy (FAP).

As a committed life long learner, and in an ongoing effort to keep up with state of the art CBT and its newest developments, he has committed himself and his staff to ongoing supervision and training in, “third generation” CBTs and mindfulness informed CBT, e.g., DBT, FAP, Compassion Informed Therapy and ACT.  He has extensive training and experience with ACT through its founders and leaders, Dr. Steven Hayes & Kelly Wilson. Additional ACT experience comes through being a past president of the NYC chapter of ACBS (Association of Contextual Behavioral Science) ACBS-NYC, and founder of Long Island ACBS, a local ACT affiliate, ACT training and peer study group. He has also trained repeatedly with master third generation clinicians such as; (DBT)Dr. Marsha Linehan & Compassion Focused Therapists (Dennis Tirch, Tara Brach & Christine Neff/Chris Germer). He has also trained and given trainings in “interpersonal” CBTs such as FAP with Drs. Mavis Tsai & Bob Kohlenberg, along with completing a one year relational psychoanalytic training at the Mitchell Institute for Relational Psychoanalysis. He is also founder & president of The “Long Island-CBT Network (”, a LI based professional CBT/EBP networking & dissemination organization as well as being on the board of Suffolk County Psych Association.  Dr Sisti, also incorporates the mindfulness insights he has garnered as a life long practitioner of TM (Transcendental Meditation), Ashtanga Yoga, and Aikido 1st Dan into his life and work.


Maria Steblai, Psy.D. Staff Therapist

Maria Steblai, PsyD., is a senior founding member of NYC Cognitive Behavioral beginning in 2004. Dr. Steblai’s long tenure at our center has made many patients and their families consider her a life long mental health resource. She obtained her doctorate from Hofstra University, where she graduated Phi Beta Kappa. Dr. Steblai obtained her initial clinical training in cognitive-behavioral therapy at Hofstra University.

Her clinical experience at North Shore University Hospital has given her invaluable expertise working with the most intense of crises in peoples lives and the opportunity to work as a team with medical/psychiatric professionals. Additionally her ongoing experience working as a certified school psychologist within several Long Island School districts, gives her broad experience with both children, adolescents, adults and families. We are very fortunate to have a professional with this much experience with childhood and adolescent disorders on staff. Her specialties include, cognitive-behavioral Therapy, ADHD, eating & body image disorders, and children-adolescent disorders. She has presented her research at psychological conventions on; attention & hyperactivity disorders (ADD & ADHD), eating disorders and body image disorders. She regularly conducts groups, workshops and seminars on ADHD, eating disorders and adolescent trauma.


Sarah Levinson, JD, LMSW Staff Therapist

Sarah Levinson received her JD from Columbia University School of Law and an MSW from SUNY Buffalo. She brings to therapy career counseling expertise from her prior career as an attorney and legal recruiter, with a focus on professional decisions and transitions, office politics and executive-level management strategy. She understands difficult personalities, high stress environments and hierarchical power dynamics. Sarah has also developed a specialty in ACT and CBT therapy for anxiety disorders (panic, trauma, social anxiety, agoraphobia, OCD, body image and eating disorders) and mood disorders. Sarah’s expertise in exposure/experiential based CBT/ACT is particularly relevant for anxiety disorders that have not responded to conventional intellectually based interventions and traditional talk therapies.

Sarah has a specialty in relationship dynamics across a wide variety of relationship structures, including parenting, navigating the complexities of modern dating, long term relationships and open relationships.  She excels at relational matters of communication, intimacy, sexuality, consent and infertility.  She has significant experience working with couples.  She has led monthly relationship discussion groups for ten years.  Sarah has also created and facilitated various workshops, panel discussions and interviews. She works with adults of all ages and adolescents, and is experienced with neurodivergent, alternative, LGBTQ and consensual non-monogamy communities.


Jenna Brick, LMSW – Staff Therapist

Jenna Brick received her MSW in 2018 from Texas State University and is currently an LMSW and New York State Certified Social Worker. Jenna enhances her clinical experience as a Cognitive-Behavioral Therapist with her background in Solution-Focused and Mindfulness-Based Therapy traditions. Working with families and communities, Jenna helps patients to understand the various systems that can affect the individuals and families with whom she is working. While working with individuals across all ages, her background as a school social worker makes Jenna an expert in applying these approaches to children and adolescents. Additionally, Jenna is a certified Children’s Kidding Around Yoga Instructor, Mental Health First Aid Instructor and has regularly conducted psychoeducational groups.

Jenna brings a humanistic focus to her work, by empowering clients to honor their strengths, collaborate more effectively with others and harness specific cognitive behavioral skills to enhance their quality of life. Her approach has been shaped by working in urban environments with adolescents, young adults and families. Jenna is interested in fostering diversity and justice by providing equal opportunities to support the social, emotional and overall well-being of her clients.

Her specialties include: Depressive Disorders, Anxiety Disorders, Trauma and Stressor-Related Disorders and Disruptive, Impulse-Control and Conduct Disorders, ADHD, as well as more general difficulties with life transitions anfamilial and relationship stress.


Kelly Ebbels, LCSW – Staff Therapist

Kelly Ebbels is a compassionate, warm and creative mental health practitioner. She brings Cognitive Behavioral Therapy (CBT) skills, alongside mindfully informed Acceptance & Commitment Therapy (ACT) skills, to her work with motivated patients. Understanding that therapy sessions are one of many places where healing can take place, Kelly helps patients identify challenges and build on strengths so they can harness their potential and facilitate change in their lives.

Kelly received her Bachelor of Arts from McGill University and her Master of Social Work from Rutgers University. With a background in housing social work and trauma therapy, she has extensive clinical and managerial experience with diverse populations in New York and surrounding areas. In her previous work as a community journalist, Kelly received multiple awards for her feature series on mental health.

Kelly’s areas of specialty include anxiety, depression, trauma, bipolar and mood disorders, substance issues, aging, chronic pain and disability. She has facilitated groups on co-occurring disorders, community building, and trauma recovery, and is at ease working with gender, sexuality, and relationship diversity, across cultural and spiritual backgrounds.


Rebecca Klouwers Office Manager

Rebecca is the office manager and is an expert problem solver, working to ensure that everything runs smoothly from billing and bookkeeping to insurance filing. If you have any sort of question or problem with logistics, you’ll likely be referred to Rebecca and she’ll be more than happy to solve your issue and support you in any way she can! Rebecca loves helping others and will be glad to assist you. Rebecca has a BFA from New York University in Theatre and Child and Adolescent Mental Studies. In addition to helping at NYC Cognitive Behavioral, she also is an executive and personal assistant for a number of other clients.


Zachary Sisti Web Developer

Zach is NYC Cognitive Behavioral’s web-developer and technician. He is responsible for overhauling the website, managing site resources and general upkeep. Zach has a BSEE from the University of Texas at Austin where he specialized in software engineering. He has professional experience in web development and academic experience in deep learning, operating system design, multicore computing and more.



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