Compassionate, evidence-based mental
health care for every stage of life
Compassionate, evidence-based mental
health care for every stage of life
We deliver comprehensive psychiatric services grounded in evidence-based standards and supported by a multidisciplinary team. Our goal is to offer clear evaluations, effective treatment options, and a supportive environment where patients feel understood and guided throughout their care.
He is a double board-certified, Harvard-trained psychiatrist practicing at Allied Psychiatry and Mental Health in Newport Beach, California.
With more than two decades of professional experience, Dr. E has vast proficiency in the mental health field.
Nasim is a compassionate psychiatric nurse practitioner committed to providing patient-centered, evidence-based care.
Ricky Koehler is a board-certified Psychiatric Mental Health Nurse Practitioner with a Doctor of Nursing Practice from UCLA.
With over eleven years of experience in family practice medicine in Irvine, CA, Tamara transitioned to psychiatry due to her passion for mental health.
She provides individualized, collaborative psychiatric care to adolescents and adults across a wide range of mental health conditions.
Clinical Excellence
Compassionate Care
Clear Communication
Evidence-Based Treatment
Patient Safety
Accessibility and Inclusivity
Collaborative Teamwork
We are dedicated to offering a supportive, respectful, and clinically grounded environment where you can feel understood and guided. Whether you are seeking an evaluation, ongoing treatment, or advanced therapeutic options, our team is here to help you take the next step with confidence.
M.D., Board Certified Psychiatrist, Board Certified Addiction Psychiatrist
Hadi Estakhri, MD — or Dr. E as his patients know him — is a double board-certified, Harvard-trained psychiatrist practicing at Allied Psychiatry and Mental Health in Newport Beach, California.
With more than two decades of professional experience, Dr. E has vast proficiency in the mental health field. At Allied Psychiatry in Newport Beach, California, his expertise is in treating a wide range of psychiatric and addictive disorders in both adult and adolescents.
Dr. E completed his medical education at the Mashhad University of Medical Sciences and his first residency in psychiatry at Tehran Institute of Psychiatry. He was an attending psychiatrist in Iran for several years before relocating to the United States for his Post-Doc fellowship at Boston University Department of Biomedical Engineering. During his fellowship, he studied the role of genetic and environmental factors in mood disorders, schizophrenia, and addiction.
Dr. E then completed his second psychiatry residency at Harvard Medical School/Boston VA Healthcare system followed by his Addiction Psychiatry subspecialty training at Mount Sinai School of Medicine, New York. During his residency, he was trained at several well-regarded institutions including Mclean Hospital and Beth Israel Deaconess Medical Center where he received specialized education in psychopharmacology for depression, ADHD, and bipolar disorder, as well as transcranial magnetic stimulation (TMS) for treatment-resistant depression. With his extensive experience at VA Boston hospitals, he became an expert in treating PTSD. Furthermore, he received numerous academic awards throughout his residency training.
Dr. E holds a holistic view of human health and emphasizes collaboration with a patient’s treatment team, including their therapist, primary care physician, and other involved specialists. He believes this is paramount to optimizing the quality of healthcare and, in turn, a better treatment outcome.
Dr. E is one of only a few psychiatrists practicing in Orange County and Los Angele area, CA who is double board-certified in both General Psychiatry and Addiction Psychiatry.
Psychiatric-Mental Health NP, PMHNP-BC
Nasim is a compassionate psychiatric nurse practitioner committed to providing patient-centered, evidence-based care. She takes a holistic approach to treating mood, anxiety, and attention disorders, helping patients achieve emotional balance and improved quality of life. Nasim’s warm and empathetic style fosters trust and collaboration, empowering patients to take an active role in their mental health journey.
Psychiatric-Mental Health NP, PMHNP-BC
Ricky Koehler is a board-certified Psychiatric Mental Health Nurse Practitioner with a Doctor of Nursing Practice from UCLA. His academic achievements include a Bachelor of Science in Healthcare Administration, a Bachelor of Science in Nursing, and a Master of Science in Nursing specializing in psychiatric mental health. A proud U.S. Navy veteran, Ricky served as a hospital corpsman, gaining invaluable experience in patient care and mental health.
Ricky’s practice focuses on a holistic approach to mental health, combining evidence-based psychiatric care with lifestyle interventions. He emphasizes the role of strength training, dietary modifications, and overall wellness in promoting mental well-being. With a commitment to compassionate and individualized care, Ricky helps his patients achieve balance and thrive in their mental health journeys.
Psychiatric Physician Assistant, PA-C
Tamara O’Nan is a dedicated psychiatric physician assistant based in Orange County, CA. Tamara’s academic background includes a Bachelor of Arts degree from UCLA with honors, followed by a Master’s degree in Physician Assistant Studies from Western University of Health Sciences. With over eleven years of experience in family practice medicine in Irvine, CA, Tamara transitioned to psychiatry due to her passion for mental health.
Tamara is committed to providing a safe and inclusive environment for patients from all walks of life. She uses a collaborative approach to help her patients find a way forward that they can feel confident in. Tamara’s
Psychiatric-Mental Health NP, PMHNP-BC
Sabrina Wahab, Psychiatric Mental Health Nurse Practitioner–Board Certified (PMHNP-BC), provides individualized, collaborative psychiatric care to adolescents and adults across a wide range of mental health conditions. She works with patients experiencing diverse emotional, behavioral, and psychiatric challenges, recognizing that no two individuals present the same way.
With five years of experience as an Emergency Room Nurse caring for acute psychiatric patients, Sabrina brings strong clinical judgment, a calm presence, and advanced crisis assessment skills to complex presentations. She provides evidence-based medication management within a whole-person framework, emphasizing education, thoughtful prescribing, and measurable functional improvement.
Sabrina strives to create a space where patients feel heard, respected, and actively involved in their care. Her focus is on developing thoughtful, sustainable treatment plans that promote long-term stability, improved functioning, and meaningful progress in everyday life.
