Alexander Van-Den-Ende, DO

Background and credentials

Dr. Jessica Matthews is a board-certified general psychiatrist. She earned her medical degree from the University of Texas Health Science Center at San Antonio and completed her psychiatry residency at Tripler Army Medical Center in Honolulu, HI. After her training, she was stationed at Fort Hood, TX, where she worked as a staff physician in the inpatient unit at Carl R. Darnall Army Medical Center and later became the inpatient medical director. She subsequently transitioned to outpatient care, serving as a staff physician and later as clinic chief in the outpatient embedded behavioral health clinics. She continued working as a staff physician after leaving the military.

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Treatment approach

Dr. Matthews specializes in medication management, often incorporating supportive and cognitive-behavioral-focused therapy into treatment. Follow-up visits typically last 30 minutes, during which she evaluates progress and adjusts treatment as needed. She takes a collaborative approach and may recommend additional therapy when she believes it will optimize patient outcomes. Her primary areas of focus include treating adults with depression, anxiety, and stress/trauma-related disorders.

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What you can expect in a first visit

During the first visit, patients can expect a comprehensive evaluation where Dr. Matthews takes the time to understand their symptoms, history, and treatment goals. She prioritizes a structured yet patient-centered approach, discussing medication management options while considering therapeutic interventions tailored to individual needs. If necessary, she may recommend additional therapy as part of a well-rounded treatment plan.

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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.

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Dr. Mullenix is a board-certified adult psychiatrist who strives to form strong therapeutic and collaborative environments with patients and values patient empowerment. Dr. Mullenix received his medical degree from the Chicago Medical School and then went on to complete his residency in psychiatry at Advocate Lutheran General Hospital. His interests and expertise are in helping patients struggling with depression, anxiety, including social/obsessive compulsive and generalized anxiety disorders, and ADHD. He provides psychiatric medication management along with supportive, cognitive behavioral therapy (CBT) and other modalities of therapeutic treatment. Dr. Mullenix's practice focuses primarily on medication management, or pharmacotherapy. He routinely incorporates supportive therapy into his 30-minute follow-up visits. Dr. Mullenix may occasionally recommend that a therapist be part of the care team to provide optimal outcomes. The philosophy of his practice is to actively involve patients in the decision-making process to improve adherence to treatment and build trusting relationships with all patients.

Dr. Thomas O’Brien holds a Bachelor of Science degree from the University of Wisconsin–Madison and earned his medical degree from Midwestern University Chicago College of Osteopathic Medicine. He completed his psychiatry residency at Loyola University Medical Center. Dr. O’Brien has experience practicing across outpatient, PHP, IOP, and inpatient settings.

He strives to create a supportive environment where patients feel heard, respected, and understood. His approach emphasizes a holistic, whole-person method to healing, guided by the patient’s own goals and values. Dr. O’Brien integrates psychotherapy with medication management, drawing on his background in psychodynamic psychopharmacology and acceptance and commitment therapy.

Dr. O’Brien focuses on understanding each patient as a whole to create individualized treatment plans. This begins with a comprehensive history during the initial session to identify biopsychosocial factors. Treatment is then tailored to align with the patient’s unique goals and values, promoting meaningful progress.

Dr. Sara Mateo holds the position of staff Psychiatrist at Talkiatry. She is a board-eligible adult Psychiatrist. Dr. Mateo completed her Medical degree at the University of Benghazi- Faculty of Medicine and finished General Psychiatry Residency training at Tower Health/DrexelPhoenixville Hospital. Throughout her career, Dr. Mateo has actively contributed to various leadership roles and committees, demonstrating her commitment to advancing medical education and promoting diversity in the field. During her training, she generously shared her knowledge through educational presentations and lectures, fostering the growth of fellow trainees and medical students. Dr. Mateo is dedicated to creating a therapeutic environment characterized by warmth, empathy, and nonjudgmental support. Her approach involves collaborating with patients to develop individualized treatment plans that consider cultural, biological, psychological, and social factors. With a primary focus on medication management, Dr. Mateo's keen interest in psychotherapy is evident, as she often integrates supportive therapy, cognitive behavioral therapy, and psychodynamic psychotherapy during 30-minute follow-up visits to optimize wellness and recovery. Dr. Mateo brings a wealth of experience in caring for individuals of diverse ages and backgrounds, adeptly addressing a wide spectrum of conditions. Her expertise extends to treating depressive disorders, bipolar disorders, anxiety disorders, trauma and stress related disorders, ADHD, OCD, Insomnia, psychotic disorders; she also has experience treating individuals with medical comorbidities.

Dr. Andrew Miller is a board-certified psychiatrist with extensive experience treating patients across Indiana. He earned his undergraduate degree in Biology with a minor in Chemistry from Indiana University, followed by his Doctorate of Medicine and residency training in psychiatry. He went on to complete a fellowship in child and adolescent psychiatry and maintains active involvement in professional organizations, including serving as past president of the Indiana Council of Child and Adolescent Psychiatry. Outside of medicine, Dr. Miller values time with his wife and two children and enjoys sports, Lego building, and supporting Indiana athletics.

Dr. Miller believes in building a collaborative therapeutic relationship grounded in respect and open communication. He strives to create a safe, supportive environment where patients of all ages—children, adolescents, and adults—feel heard and understood. He works to balance medical expertise with patient preferences, encouraging shared decision-making and honoring each individual’s goals in treatment.

Dr. Miller begins with a thorough evaluation to gain a complete understanding of each patient’s history, strengths, and challenges. From there, he develops a personalized treatment plan that may include therapy, medication management, and integration of other supportive resources. He is committed to ongoing follow-up, adjusting care as needed, and helping patients move toward lasting improvement in their mental health and overall well-being.

Dr. Erlach is a board certified adult psychiatrist who has previously worked for the United States Air Force and the Department of Veterans Affairs. He attended medical school at the Uniformed Services University of Health Sciences, graduating in 2009, followed by active duty military service in the United States Air Force until 2024. He completed residency training at the combined military-civilian Wright State University/Wright Patterson AFB training program in Dayton, Ohio.

Dr. Erlach enjoys working with all types of patients. He takes a collaborative approach to patient care and develops a treatment plan alongside the patient so that both are fully invested in the plan. He generally has weekend and evening appointments only.

Dr. Erlach incorporates therapy into medication management appointments. Dr. Erlach feels that addressing psychosocial stressors and developing coping mechanisms are a vital component to treatment.

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