Dennis Valerstain, MD

Dr. Robben proudly served in the U.S. Air Force and has been practicing psychiatry for 17 years. He is happy to have completed his medical school education, as well as his residency in general psychiatry and fellowship in addiction psychiatry, all at the University of South Florida in Tampa. Dr. Robben is board certified in both general psychiatry and addiction psychiatry. He has experience in many roles over the span of his career to include working with Veterans diagnosed with posttraumatic stress disorder and substance use disorders, managing specialty clinics for patients with treatment-resistant depression, and working in general outpatient psychiatry clinics, as well as emergency and inpatient psychiatric settings. Dr. Robben also previously served as the Training Director for the University of South Florida Morsani College

of Medicine Addiction Psychiatry Fellowship Program. He is currently the Medical Director at a residential substance use disorder treatment center in Florida. Additionally, Dr. Robben is a certified Medical Review Officer and has additional qualifications in transcranial magnetic stimulation (TMS) and Spravato.

(esketamine). Dr. Robben has been voted as Addiction Medicine "Top Doctor" in Tampa Bay, FL by physicians for 8 of the last 9 years. Dr. Robben specializes in treating depression, bipolar disorder, anxiety, PTSD, OCD, ADHD and substance use disorders.

Dr. Robben uses a supportive, patient-centered approach, taking into account each individual's personal values and goals when formulating a treatment plan. He educates patients on the most up to date scientific evidence and provides multiple treatment options to help each person determine the most appropriate plan for them.  

Dr. Robben believes in a collaborative and holistic approach to working with his patients. Dr. Robben spends a significant amount of time educating his patients on all forms of mental health treatment, from medications and psychotherapy, to nutrition, exercise, meditation and sleep hygiene. What works well for

One person may not work well for another person. Having options and understanding the potential benefits and risks of each treatment empowers patients to take an active role in their own healthcare.

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Dr. Jonathan Hertz is board-certified in adult psychiatry. He completed fellowships in child and adolescent and public psychiatry and has been practicing psychiatry for over 18 years. Dr. Hertz's practice focuses on medication management which is offered with supportive and/or dynamic psychotherapy within 30-minute follow-up sessions. If patients have individual psychotherapists, Dr. Hertz will work collaboratively with these providers within a treatment-team approach to patient care delivery. Dr. Hertz received his medical degree from Tufts University School of Medicine in Boston. He remained in Boston to complete a residency in adult psychiatry at Cambridge Health Alliance and a fellowship in child and adolescent psychiatry at Children's Hospital Boston. Dr. Hertz subsequently returned to his hometown of NYC and completed a fellowship in public psychiatry. Dr. Hertz has clinical and administrative experience in the field of psychiatry. These positions include ACT Team community psychiatrist, director of adult outpatient clinic, and medical directorship in behavioral health within community hospitals. With training in child/adolescent, adult, and public psychiatry, Dr. Hertz has a developmental approach to mental health care. That is, he collaboratively explores the bio-psychosocial factors that may have influenced the development of mental disorders. Dr. Hertz believes an ecological approach enables a broader view of the multip

Background  and credentials    

Dr. Christa DeFries is a board-certified Adult Psychiatrist. She earned her  medical degree from UT Southwestern Medical School in Dallas, Texas, and  completed her residency in Adult Psychiatry at Baylor Scott & White in  Temple, Texas. Following residency, Dr. DeFries gained additional experience  treating homeless and formerly homeless populations in New York City,  particularly focusing on individuals with histories of trauma and substance  addiction, prior to joining Talkiatry.    

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Treatment approach    

Dr. DeFries practices Adult Psychiatry, employing an integrative treatment  approach combining medication management, psychotherapeutic methods, and  lifestyle modifications. She recognizes that each patient benefits from a  personalized mix of these three aspects of care. Dr. DeFries specializes in  treating diverse psychiatric conditions, including those related to trauma,  substance addictions, and various mental health disorders.    

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What you can expect in a first visit    

In a first visit with Dr. DeFries, patients can expect a comprehensive  evaluation aimed at understanding their individual mental health history,  specific concerns, and overall treatment goals. Dr. DeFries emphasizes an  individualized approach, carefully exploring the best combination of  medication, therapy, and lifestyle adjustments tailored specifically to each  patient's needs. Patients can anticipate an empathetic and collaborative  environment focused on their personal experiences and goals.    

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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. Michael Petetit has worked with people from many different walks of life in clinics, hospitals, and online, providing evidence-based treatments for a wide range of mental health conditions. His professional journey is unique—he began his career as a research chemist, later earned a Master’s degree in psychology and worked with children, before pursuing his medical degree and completing a psychiatry residency.

Dr. Petetit approaches treatment as a true collaboration. He partners with patients to clarify goals and create individualized treatment plans that reflect their priorities and values. He strives to be non-judgmental, direct, and honest in his style, building a therapeutic relationship that supports open communication and trust.

Dr. Petetit begins with a thorough evaluation to understand each patient’s circumstances and challenges. From there, he works with patients to set and prioritize goals, review treatment options, and select a plan that feels both comfortable and practical. As treatment progresses, he regularly revisits and refines the plan, ensuring it remains effective and aligned with the patient’s evolving needs.

Dr. Mary Stephenson is a board-certified Child and Adolescent Psychiatrist with more than 25 years of clinical experience working with this population. Dr. Stephenson's practice focuses on medication management. She believes that the support and involvement of the family are an integral part of the treatment of the client. Additionally, more therapy support may be needed on occasion, and the recommendation to bring a psychotherapist on the care team may occur to provide an optimal outcome. She received her medical degree from Wright State University in Dayton, Ohio. She completed her psychiatry residency at the University of Louisville School of Medicine, and her child and adolescent training at the Bingham Child Guidance Center, also part of the University of Louisville, in Louisville, Kentucky. After completion of her training, she moved to Colorado where she worked at The Cleo Wallace Center, in Westminster, CO, providing care for hospitalized youth, and clients in the Day Treatment and Residential setting. In 2000, Dr. Stephenson became the primary Child and Adolescent Psychiatrist on the outpatient team at Denver Health Medical Center in Denver, Colorado. Her role was providing diagnostic evaluations, and medication management in Federally Qualified Health Centers (FQHCs), and the hospital clinic, working closely with residents, child fellows, and other trainees. She had an academic appointment through the University of Colorado School of Medicine. She treated a varied demographic and had a wide range of diagnoses in the child and adolescent population. From 2016-2021, she worked at Intermountain Health Center in Tucson, AZ providing care in the outpatient setting of the community mental health center. The care was a hybrid model of "in-person” and Telehealth treatment of children and adolescents with various disorders, with an emphasis on diagnostic evaluations of Autism and Autism spectrum disorders.‍

Dr. Catherine Bledowski is board-certified in General Psychiatry and Consultation-Liaison Psychiatry (Psychosomatic Medicine) by the ABPN.  She received her medical degree from the University of South Carolina School of Medicine and completed her residency in General Psychiatry as well as her fellowship in Consultation-Liaison Psychiatry (Psychosomatic Medicine) at Virginia Commonwealth University.  Dr. Bledowski spent most of her career in large, urban academic medical centers, primarily taking care of patients with severe mental illness, as well as those with mental illness comorbid with other complex medical conditions.  

Dr. Bledowski has a passion for medical education and has held faculty appointments at Virginia Commonwealth University, University of Utah, Georgetown University, George Washington University, and Walter Reed National Military Medical Center.  Dr. Bledowski has authored numerous peer-reviewed journal articles and provided academic presentations to both national and international audiences.  Her interests include emergency psychiatry, brain stimulation therapies, complex psychopharmacology, and psychopharmacology in the medically ill.  Prior to joining Talkiatry, Dr. Bledowski held various leadership positions in academic medicine, emergency psychiatry, consultation-liaison psychiatry, and brain stimulation at multiple academic medical centers.  

Dr. Bledowski's approach to patient care is centered upon collaboration and utilizing the most up-to-date evidence-based practices.