Marc Whaley, MD

Background  and credentials    

Dr. Columban Heo is a board-certified psychiatrist. He earned his medical  degree from Touro University Nevada and completed his residency at Unity  Health White County Medical Center. Dr. Heo further specialized by completing  a fellowship in Consultation-Liaison Psychiatry at the Cleveland Clinic,  where he gained extensive experience working within multidisciplinary  healthcare teams, particularly focused on psychiatric care for patients with  complex medical conditions.    

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Treatment approach  

Dr. Heo specializes in treating a broad range of psychiatric conditions,  notably mood and anxiety disorders. He integrates medication management with  a holistic, personalized approach to treatment, emphasizing the  interconnectedness of mind, body, and spirit. Dr. Heo believes in tailoring  treatment plans individually, combining therapy and medications to suit each  patient’s unique needs, and highlights the importance of healthy  relationships in achieving overall mental health.    

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What you can expect in a first visit    

Patients visiting Dr. Heo for the first time can expect a comprehensive and  personalized assessment that explores not just their psychiatric symptoms but  their overall well-being and personal relationships. Dr. Heo prioritizes a  holistic evaluation, carefully balancing medication considerations and  therapeutic interventions tailored specifically to each patient’s situation  and goals. He creates an empathetic, collaborative atmosphere to discuss and  develop personalized plans for mental and emotional wellness.  

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Why Talkiatry?    

We’re a virtual mental health practice that makes it easy to find great  care. We combine quality and convenience to help you thrive—faster. Our  providers, like this one, are highly trained experts who specialize in  medication management and collaborate with you on a treatment plan that fits  your needs and comfort level.

Dr. Parker Loy holds the position of Staff Psychiatrist at Talkiatry. After finishing undergraduate studies at the University of Tennessee, Knoxville, he completed the University of Tennessee Health Science Center (UTHSC) Master of Science program before enrolling in medical school at the same institution. After graduating from medical school, he completed his residency at UTHSC, during which he trained in a variety of inpatient and outpatient settings and treated a broad spectrum of mental health conditions. He enjoys treating a wide variety of conditions, including mood and anxiety disorders. Therapeutic techniques are incorporated into medication management visits when indicated, and collaboration with therapists may also be recommended.

Dr. Irene Pastis is a board-certified psychiatrist who specializes in adult psychiatry.  She completed residency training at East Carolina University in both internal medicine and psychiatry.  After residency, she pursued her passion in psychiatry and stayed on as a clinical assistant professor in the department of psychiatry at East Carolina University.  In this role she specialized in treating adults with mental illness in both the inpatient and outpatient settings.  She has spent a considerable amount of time teaching residents and medical students and has published several papers focusing on the neuroscience pathways of mental health conditions.  In her daily practice, Dr. Pastis focuses on evidence-based treatments utilizing the latest clinical guidelines and current approved treatments.  In addition to medication management, she also incorporates psychotherapy in the treatment of mental health conditions.  Dr. Pastis is passionate about taking a collaborative approach with her patients to help them reach their potential.

Dr. Katelyn Thompson is board certified in Adult Psychiatry. Patients looking for a psychiatric provider will find that Dr. Thompson has a gentle and approachable style. She believes that each patient was created on purpose and for a purpose. The brain is deeply wired for resilience, and Dr. Thompson is blessed to witness tDr. Katelyn Thompson is board certified in Adult Psychiatry.  

Patients looking for a psychiatric provider will find that Dr. Thompson has a gentle and approachable style.  She believes that each patient was created on purpose and for a purpose.  The brain is deeply wired for resilience and Dr. Thompson is blessed to witness that while supporting that in her patients.  She focuses on medication management with supportive psychotherapy as she treats a wide variety of psychiatric diagnoses.

his while supporting her patients. She focuses on medication management with supportive psychotherapy as she treats a wide variety of psychiatric diagnoses.‍

Dr Reddy is double board certified in adult as well as child and adolescent psychiatry. She has experience working at various levels of mental health care. Dr. Reddy has most recently served as the medical director for a partial hospitalization/intensive outpatient program (PHP/IOP) for adolescents in the Dallas/Fort Worth area. She completed her general psychiatry residency at the University of Illinois at Peoria and went on to pursue her child and adolescent psychiatry fellowship at the University of Texas Southwestern. She is knowledgeable in treating patients of all ages and a wide variety of diagnoses including depression, bipolar disorder, anxiety, ADHD, OCD, PTSD, and eating disorders. Dr. Reddy is passionate about working with LGBTQIA+ populations, providing culturally informed care, and taking a person-centered approach to providing comprehensive and individualized treatment to her patients. She is well versed in incorporating psychotherapy in conjunction with medication management. She has experience in incorporating supportive, cognitive behavioral, and dialectical behavioral therapeutic approaches in her care.

Dr. Michael Gravenstein earned his medical degree from the University of Florida College of Medicine, where he also completed his psychiatry residency. During training, he was recognized with multiple awards, including the Malcom Randall VA Resident of the Year Award, the Ross A. McElroy Psychotherapy Award, and the John “J.D.” Dorian Award for best sense of humor. He has worked across outpatient, inpatient, and consult liaison settings, and has experience treating a wide range of conditions including depression, anxiety, ADHD, OCD, personality disorders, and transitional age concerns. He also has expertise working with LGBTQIA+ patients and provides psychodynamic, CBT, and supportive therapies.

Dr. Gravenstein believes in a comprehensive approach to treatment that integrates medications, therapy, and lifestyle interventions. While medications can be very effective, he views them as just one part of a broader treatment plan tailored to each patient’s needs. He emphasizes individualized care and sees treatment as a team effort, meeting patients where they are and progressing at a pace they feel ready for.

Dr. Gravenstein strives to create a warm, collaborative environment that fosters open communication and genuine connection. He may challenge patients therapeutically but always with careful attention to their readiness and comfort. His goal is to build trust so that meaningful conversations and progress can occur. For him, success is always shared—when patients succeed, they succeed together; when challenges arise, they regroup and move forward together.