Christa DeFries, MD

Dr. Nelson is a board-certified psychiatrist who attended the University of Iowa Medical School and completed her psychiatry residency and child and adolescent psychiatry fellowship at Walter Reed National Military Medical Center.  She has extensive experience treating active-duty service members, family members of active duty and the veteran population.  She feels comfortable working with a wide range of age groups and enjoys treating challenges with anxiety, mood, sleep, and concentration.

Dr. Nelson believes that the key to success in mental health care is being able to establish a trusting and open relationship between psychiatrist and patient.

While initial sessions include the need to gather background information about the patient overall as well as the symptoms of concern, subsequent sessions are focused on learning the impact of the treatment.

‍

Dr. Arjun Kaverimanian is an adult psychiatrist with a clinical approach emphasizing the intersection of medication-based treatment and talk therapy. He earned his medical degree from Saint Louis University School of Medicine, after which he completed his psychiatry residency training at Loyola University Medical Center. During his training, he gained experience across a wide range of mental health settings, including community mental health centers and the Department of Veterans Affairs, and worked at various levels of care—from inpatient units to partial hospitalization and intensive outpatient programs, as well as outpatient clinics.

Dr. Kaverimanian has cultivated a robust skill set in psychotherapy techniques—including psychodynamic therapy, Acceptance and Commitment Therapy, Cognitive Behavioral Therapy, supportive therapy, and mindfulness-based approaches—which he integrates alongside evidence-based medication management.

Dr. Kaverimanian is committed to understanding each patient as a whole, taking into account the interplay of psychological, social, and biological factors that shape a person's mental health. He has particular areas of interest in the treatment of depression, anxiety, and post-traumatic stress disorder.

‍

Bethanie is a board-certified Mental Health Nurse Practitioner who earned her Psychiatric Mental Health Nursing credentials and a Master’s in Psychiatric and Mental Health Nursing from Columbia University School of Nursing, where she was inducted into the Sigma Theta Tau Nursing Honor Society. She has been in practice for over 10 years, providing care to individuals with anxiety, depression, bipolar disorder, and schizophrenia. Bethanie also has a strong passion for supporting women’s mental health during the perinatal phase of life.

She believes in a collaborative partnership with her clients, working together to develop a mutually agreed-upon plan of action that maximizes the chances of success.

‍

Dr. John Weller, MD, is a psychiatrist with a strong foundation in science and clinical care. He earned his undergraduate degree in molecular genetics from the University of Vermont and conducted neuroscience research in both academic and industry settings. A graduate of St. George’s University School of Medicine, he completed his psychiatry residency at Mather Hospital, Northwell Health, where he was honored as Resident of the Year in 2025 and inducted into the Alpha Omega Alpha Honor Medical Society.

Dr. Weller is committed to providing compassionate, evidence-based care that considers the full spectrum of biological, psychological, and social factors. He builds therapeutic relationships on empathy, respect, and trust. By tailoring treatment plans to each patient’s personal and cultural context, he helps individuals take control of their mental health and work toward long-term recovery and resilience.

In the first session, Dr. Weller takes time to listen carefully and gather a thorough understanding of each patient's concerns, history, and current functioning. He uses empathy and active listening to foster open communication and develop personalized treatment plans that may include therapy, medication, or lifestyle changes, with the goal of restoring wellness and stability.

*THIS PROVIDER CANNOT PRESCRIBE CONTROLLED SUBSTANCES FOR NH PATIENTS* Dr. Peter Truong is a board-certified psychiatrist trained in Adult Psychiatry. He received his medical degree from FIU Herbert Wertheim College of Medicine in Miami, Florida, and completed his residency training at Cambridge Health Alliance – Harvard Medical School.

Dr. Truong treats each patient with a holistic, evidence-based approach that incorporates psychopharmacological and psychotherapeutic best practices. His priority is to build a safe and trusting working relationship with each patient, keeping in mind their unique biological, psychological, social, and spiritual contexts.

Dr. Truong has extensive experience treating depression, anxiety, ADHD, and trauma-related disorders. He incorporates therapy modalities such as supportive, psychodynamic, CBT, and EFT. Other professional interests include LGBTQIA and college mental health, mindfulness, and interventional psychiatry. He has worked with individuals with diverse backgrounds from all walks of life.

Dr. Stephen Geisler is a board-certified adult psychiatrist and has been practicing for over 37 years. His practice focuses on medication management, and typically offers this in conjunction with supportive therapy in 30-minute follow-up visits. If Dr. Geisler feels you would benefit from working with a therapist in conjunction with medication management, he welcomes collaboration with your therapist to make for the best outcome. Dr. Geisler is a graduate of the New York University School of Medicine. He completed a fellowship in Psychoanalytic Psychotherapy at the Zucker Hillside Hospital of Northwell Health after finishing his residency training there. He is currently an Assistant Clinical Professor at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell. Over the years Dr. Geisler has received a number of awards including NAMI Exemplary Psychiatrist Award, The APA Irma Bland Certificate of Excellence in Teaching Residents, the Zucker Hillside Hospital Department of Psychiatry Recognition Award for Education, and twice received the Outstanding Teacher of the Year Award from the graduating residents' class. Dr. Geisler is a member of the American Psychiatric Association, the Nassau Suffolk District Branch of the APA and the American Society of Clinical Psychopharmacology. Through the years, Dr. Geisler has participated in many clinical research projects, has been the co-author of many papers, and has made many presentations. Dr. Geisler specializes in psychopharmacology, especially tailoring individualized treatment to serve the needs of patients with a variety of conditions. He has a lot of experience in treating patients with depression, bipolar disorder, anxiety disorders, ADHD, and OCD.