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Headshot of psychiatrist Dr Melissa Deuter MD owner of Sigma

Dr. Melissa Stennett Deuter, MD

Dr. Melissa Deuter is a board certified psychiatrist in San Antonio, Texas and founder of Sigma Mental Health Urgent Care. Dr. Deuter received her undergraduate degree from the University of Arkansas and attended medical school at the University of Arkansas for Medical Sciences. She completed Psychiatry residency at the University of Texas Health Science Center San Antonio and served as Chief Resident in 2003-2004. She is a member of the teaching faculty in the Department of Psychiatry at UTHSCSA School of Medicine and also at the new UIW-COM School of Medicine in San Antonio. She is a former President of the Bexar County Psychiatric Society, a current member of the Texas Society of Psychiatric Physicians (TSPP) Ethics Council, and a current member of the South Texas Psychiatric Physicians Research Network’s Executive Committee. She has been recognized as a San Antonio “Top Doctor” and a “Best of” Doctor, and has received the American Registry “Patient’s Choice Award.” Dr. Deuter has a special interest in urgent psychiatric care and early intervention, new onset psychiatric illness, and differentiating serious illness from normal brain development. She is the author of A Vision for Change: How to Help Someone with Addiction or Mental Illness, a practical guide for families who see signs of mental illness or addiction in a loved one, but don’t know where to begin getting help.

Dr. Deuter is also the author of STUCK in the Sick Role: How Illness Becomes An Identity available on Amazon:

Headshot of geriatric psychiatrist Dr Sandra Vale MD

Dr. Sandra Vale, MD

Sandra D. Vale, M.D. is the supervisory behavioral health medical director for Superior Health Plan.  She was previously the Texas Medical Director for Cenpatico Behavioral Health serving Superior Health Plan of Texas.  She was most recently the Medical Director of Adult Behavioral Health at the Center for Health Care Services (CHCS) of Bexar County in San Antonio, Texas.  While at CHCS, she also served as the lead psychiatrist for the Assertive Community Treatment (ACT) program and Intensive Outpatient Commitment Program (IOPC).  In previous years she served as the Chief of Behavioral Health at WellMed Medical Group where she developed an integrated behavioral health program for WellMed’s primary care clinics.  She also served as the director of psychiatry services at the San Antonio State Supported Living Center which works with the intellectually challenged/psychiatrically challenged dual diagnosis adult population.


Dr. Vale is a native San Antonian.  She attended the University of Texas at San Antonio and completed medical school at the University of Texas Health Science Center at San Antonio (UTHSCSA).  Dr. Vale completed her residency training in General Adult Psychiatry at the University of Texas Medical Branch (UTMB) at Galveston where she served as Chief Resident during her final year of residency.  She completed additional Fellowship training in Geriatric Psychiatry at the University of Texas Health Science Center in San Antonio and continues to focus on the geriatric population through her clinical work.  She has received numerous awards and recognition for her clinical care and teaching to most recently include being recognized as one of San Antonio’s top physicians.  Dr. Vale sees herself as a champion for transformation of healthcare systems that are integrated, person centered, and quality focused.

Headshot of psychiatrist Dr Christine Masuda MD

Dr. Christine Masuda, MD

Dr. Christine Masuda is a board certified psychiatrist in Austin, Texas. She received her undergraduate degree from the University of Washington before moving to Texas to serve in Teach for America as a high school science teacher. She attended medical school at the University of Texas Southwestern and completed psychiatric residency at the University of Texas at Austin Dell Medical School.


During her residency, she did a senior selective in psychiatric emergency medicine and saw firsthand the need for more psychiatric urgent care resources. Following residency, she served as a psychiatrist for Harris Health in Houston, where she practiced psychiatry integrated in a family practice setting. 


Dr. Masuda values evidence based medicine and the close partnership of psychiatry with psychotherapy. She completed cognitive processing therapy training which impressed upon her the power in approaching mental illness with multiple modalities.

Headshot of psychiatrist Dr Sarah Gutierrez-Hernandez MD

Dr. Sarah Gutierrez-Hernandez, MD

Dr. Sarah Gutierrez-Hernandez, M.D. (or Dr. Gutierrez) is a psychiatrist practicing in both Austin, TX and San Antonio, TX. She earned her Bachelor’s of Science degree at the University of Notre Dame where she studied Biological Sciences and minored in Theology. While in college, Dr. Gutierrez searched for clinical volunteering opportunities in Austin during the summer months and had the opportunity to volunteer at Seton Shoal Creek psychiatric hospital. This is where Dr. Gutierrez was initially exposed and very much drawn to the field of psychiatry. Dr. Gutierrez obtained her medical degree from the University of Texas Health Science Center at San Antonio at the Long School of Medicine. She then remained at UT Health San Antonio to complete her psychiatric residency. At this residency program, Dr. Gutierrez was able to train with a diverse patient population including patients at University Hospital, veterans at Audie L. Murphy Memorial Hospital, active duty military at Brooke Army Medical Center, and students at UT Health Student Counseling Center. Dr. Gutierrez is very passionate about working with each patient to assist them in their journey towards, not only feeling better, but achieving their full potential and she is excited to join the team at Sigma where the mental health urgent care model allows her to help patients in crisis.

Headshot of Caroline Horton PA-C prescriber

Caroline Horton, PA-C

Caroline is a Physician Assistant and is nationally certified by the National Commission on Certification of Physician Assistants. She received a Master in Physician Assistant Studies at James Madison University in Virginia and is licensed to practice in the state of Texas by the Texas Medical Board. She has experience in Emergency Medicine and the care of adults and children with acute and chronic mental health disorders in the emergency room setting. She is committed to helping provide mental health services to the people of San Antonio and the surrounding communities that allows more people to access the care they need in an outpatient setting.

Headshot of Gina Seyfried PMHNP prescriber

Gina Seyfried, PMHNP

Gina Seyfried is a family psychiatric nurse practitioner in the state of Texas with 31 years of Nursing experience, 27 of those years in the Emergency Department.  Gina graduated with her Family Nurse Practitioner certification from Walden University in 2015.  In 2018, she received her Psychiatric Mental Health Nurse Practitioner certification from University of Texas Rios Grande Valley.  She currently works at Center for Healthcare Services and that's where she recognized the need to go back to school to get her certification in Mental Health.  Gina is Passionate about helping individuals dealing with mental health.

Headshot of Thomas Dietz PMHNP prescriber

Thomas Dietz, PMHNP

Thomas is a psychiatric mental health nurse practitioner that is board certified by the American Nurses Credentialing Center. Prior to becoming a nurse practitioner, he started his career in the healthcare field as a nationally registered paramedic. In 2004 he joined the U.S. Army with a military occupational specialty of health care specialist (combat medic). He served a one-year tour in Iraq from 2008-2009. It was his experience in Iraq which led him to eventually pursue a career in Mental Health. As a registered nurse he worked in both drug research and with a pediatric special needs population.

His practice style involves putting an emphasis on truly listening to his patients. He believes that everyone is unique and treatments are not “one size fits all”. He adopts a holistic health approach that combines medication management along with lifestyle modifications.

Headshot of Dexter Brown LPC therapist

Dexter Brown, LPC

Dexter is a Licensed Professional Counselor who completed his Masters of Science degree in Marriage and Family counseling at Prairie View A&M University.  Dexter currently provides clinical services at Sigma Mental Health Urgent Care and trauma focused equine assistant psychotherapy (TF-EAP) at Courage Ranch.  His focus includes adolescents and families who have been impacted by adverse childhood experiences (ACEs).  There are many forms of trauma which can disrupt an individuals' ability to connect with themselves and others, as well as cause other mental health issues.  He believes creating a safe space and a healthy therapeutic relationship with individuals can create a pathway for healing.  In addition to providing different alternatives to address presenting problems, developing and exploring meaning behind behavior can be empowering.

Headshot of Astrid Truss LPC therapist

Astrid Truss, LPC

Astrid Truss is a licensed professional counselor dedicated to assisting individuals, couples, and young adults on their journey toward living their best lives. With a compassionate heart and a commitment to understanding, she strives to create a safe and supportive space for diverse populations facing a range of mental health challenges.

Her approach is grounded in kindness and genuine desire to help others navigate the complexities of life. She believes in the power of connection and collaboration, working alongside her clients to explore their unique experiences and develop personalized strategies for growth.

She specializes in working with individuals suffering from depression, self-esteem issues, anxiety, grief, anger and crisis situations. Whether it’s providing support during times of crisis or fostering personal development in a more long term capacity, she is able to assist in the healing process.

In addition to her work with individuals, she also works with couples, recognizing the unique dynamics that relationships bring. She helps couples explore effective communication, strengthen connections, and work towards building a fulfilling and supportive partnership.

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