Matthew Koller, MD

Xavier Diao, MD (he/him) is a board-certified psychiatrist. He earned his undergraduate degrees in Psychology and Biological Sciences at the University of Maryland, where he also obtained his medical degree. Dr. Diao completed his psychiatry residency at the Icahn School of Medicine at Mount Sinai, received additional training in child and adolescent psychiatry at Columbia and Cornell, and finished a psychoanalytic fellowship at the New York Psychoanalytic Society & Institute. Prior to joining Talkiatry, he was an Assistant Professor of Clinical Psychiatry at the University of Pennsylvania, where he provided clinical care and teaching along the undergraduate-graduate medical education continuum.

Dr. Diao's therapeutic orientation is informed by psychodynamic, cognitive behavioral, and dialectical behavior modalities. He has expertise in the treatment of a diverse range of mental health conditions, including depression, anxiety, OCD, and PTSD. Dr. Diao uses a developmentally informed and LGBTQ-affirmative approach in his practice, with the aim of enriching meaning and alleviating suffering in the domains of work, play, and love.

Dr. Diao begins each encounter with gentle curiosity, inviting patients to share their stories without fear of judgment. Together, he crafts an individualized treatment plan with the patient that may include medication, psychotherapy, and/or referrals to subspecialty care, always in close collaboration with other members on the treatment team.

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Dr. Richard McCall is a board-certified psychiatrist with over 25 years of comprehensive experience in delivering exceptional mental health services across various settings. He received his medical degree from the University of Virginia School of Medicine and completed his Psychiatry residency training at Duke University School of Medicine. He treats adult patients of all ages and is known for a compassionate, patient-centered approach. Dr. McColl integrates psychopharmacology with multiple psychotherapy modalities. He has specialized training in psychodynamic psychotherapy, Cognitive Behavioral Therapy (CBT), Dialectical Behavior Therapy (DBT), Acceptance and Commitment Therapy (ACT) and more. He looks forward to helping patients reach their goals for mental health care while providing a compassionate and collaborative environment.

Dr. McGowan is a board-certified adult psychiatrist with over 14 years of experience, during which time he primarily treated active-duty US Navy sailors, their family members, and military retirees in the outpatient setting. His practice focuses on medication management in addition to supportive and cognitive-behavioral therapy in 30-minute follow-up visits. He is a strong advocate of multiple treatment modalities and, in certain situations, may suggest that therapy and/or regular physical exercise be included in your treatment plan to provide the best outcome. He received his B.S. in Physics from the United States Naval Academy. After serving as an Intelligence Officer in the Navy for eight years, he transitioned to medicine and earned his medical degree from the Uniformed Services University of the Health Sciences in Bethesda, MD. After completing an intern year in Family Medicine, Dr. McGowan completed residency training in Psychiatry at Naval Medical Center Portsmouth, VA, where he remained on staff for the next ten years and was primarily involved in resident training and education. He held academic appointments at the Uniformed Services University and Eastern Virginia Medical School and served as the Psychiatry Residency Program Director for six years. He served his final four years in uniform running the behavioral health department at Naval Air Station Whidbey Island, WA. He recently retired from the Navy after a 30-year career. Dr. McGowan has extensive experience in outpatient psychiatric care. In addition to the full spectrum of mood and anxiety disorders, he has treated a very large number of patients with PTSD stemming from combat, natural disasters, and sexual trauma. He believes that, like his service to the country, working alongside others in their journey to better mental health is an incredible privilege.

Dr. Sharon Kahler is Board Certified in Adult and Child & Adolescent Psychiatry and treats patients of all ages. She has over a decade of experience in both community mental health centers and private practice, working with individuals from diverse backgrounds. She earned her medical degree from New York Medical College, completed Adult Psychiatry Residency at New York-Presbyterian/Weill Cornell, and completed Child and Adolescent Fellowship training at NYU Langone and Bellevue Hospital. Her clinical interests include mood and anxiety disorders, PTSD, and childhood psychiatric disorders.

Dr. Kahler is committed to providing compassionate, high-quality mental health care. She fosters a therapeutic, nonjudgmental environment where patients can openly share their concerns and values. Viewing treatment as a partnership, she encourages patients to play an active role in their care and takes a whole-person approach, considering lifestyle, environmental, and social factors that contribute to healing.

Dr. Kahler begins with a comprehensive assessment to understand each patient’s history, background, and treatment priorities. She develops individualized treatment plans using evidence-based approaches, supporting patients in navigating life’s challenges and finding a path to mental wellness.

Tamara Lazenby, MD is a board-certified psychiatrist with more than 20 years of clinical and academic experience in emergency mental health, disaster response, and trauma-focused care. She earned her undergraduate degree at George Mason University and completed her medical degree at Eastern Virginia Medical School. After the September 11th attacks, Dr. Lazenby trained in psychiatry at New York Medical College’s Saint Vincent’s Hospital, specializing in emergency and trauma psychiatry.

She previously served as Associate Director of Wellness & Emergency Response Services at New York University’s Student Health Center, leading a team that cared for more than 50,000 global NYU students. Dr. Lazenby also previously served as Staff Psychiatrist and Team Lead for the Combat PTSD Clinical Team at the Hampton VA Medical Center, providing care for veterans with service-related trauma and implementing National VA Standards of Care.

Dr. Lazenby believes healing happens when mind, body, and spirit are aligned. She creates a compassionate and collaborative environment where patients feel deeply heard and empowered in their own care. Her approach blends conventional psychiatric treatment with nutrition, mindfulness, movement, and stress-reduction strategies to support long-term mental wellness.  She values authenticity, open communication, and shared decision-making, empowering patients to build resilience and restore balance in their lives.

She begins with a comprehensive assessment exploring medical, psychological, and lifestyle factors that influence mental health. Treatment plans are personalized and may include psychotherapy, targeted laboratory testing, lifestyle modifications, supplements, and medication when appropriate. Dr. Lazenby works closely with patients to restore balance, resilience, and overall well-being through a truly integrative approach. Regular collaboration and feedback, helping patients heal, grow, and thrive.

Dr. Stephen Byrd is a clinical psychiatrist at Talkiatry. He is board-certified in both psychiatry and addiction medicine. He has been practicing for over 31 years in a wide variety of settings, including working with inpatients and outpatients in private practice, community mental health, geriatric, VA, and community hospital/medical center settings. Dr. Byrd's practice focuses on evidence-based medication management, usually provided in conjunction with 30-minute supportive psychotherapy, which is informed by cognitive behavior therapy, psychodynamic psychotherapy, and motivational enhancement. When more intensive therapy is needed, Dr Byrd may ask you to include a therapist as part of your care team. He received his medical degree from the University of Cincinnati College of Medicine in Ohio and completed his residency training in psychiatry at Case Western Reserve University School of Medicine, University Hospitals of Cleveland. Throughout his career, he has treated patients with a wide variety of conditions in both inpatient and outpatient settings. Additionally, He has served as director of inpatient geropsychiatry at Lutheran Hospital in Cleveland, Ohio, program manager of the substance abuse treatment program at the Charlie Norwood Veterans Affairs Medical Center in Augusta, Georgia, and medical director of outpatient behavioral health at Saint Alphonsus Regional Medical Center in Boise, Idaho. Throughout his career, Dr. Byrd has been active in training medical students and psychiatry residents, and he has held clinical teaching appointments at Case Western Reserve University School of Medicine, Northeastern Ohio Universities College of Medicine, Medical College of Georgia, University of Washington School of Medicine, Idaho College of Osteopathic Medicine and Pacific Northwest University of Health Sciences College of Osteopathic Medicine.�.�