714-545-5550 Monday/Friday 9am - 5pm

Clinical Staff


Nurse Practitioners / Physician Assistants


Alejandro Alva, M.D.

Psychiatrist and PNS Founder

Dr. Alva received his education at the California State University of Fullerton and the Autonomous University of Guadalajara Medical School. After he completed his education and training in Guadalajara, Mexico, he returned to California to finish his residency at the University of California Irvine.

Prior to Dr. Alva's formation of PNS, he was involved in multiple endeavors including inpatient and outpatient work as well as clinical research in both Los Angeles and Orange counties. Dr Alva's focus is on the latest treatments available for psychiatric disorders, chemical/alcohol dependence as well as aspects of ethnicity and their correlation within pathological states. Dr. Alva has many years of experience in serving the medical community in various capacities; as a patient advocate, clinician, researcher and medical director. Dr. Alva's expertise in adolescent, adult and geriatric psychiatry as well as chemical/alcohol dependence and his treatments in psychiatric disorders make him one of the nation's most prominent psychiatrists.

Dr. Alva is a member of multiple professional organizations, including the American Medical Association, the Orange County Medical Association, the American Psychiatric Association, the California Psychiatric Association, the American Board of Forensic Medicine, the American College of Forensic Examiners, the American Board of Psychopharmacology, the California Hispanic American Medical Association, the New York Academy of Science, the American Association for the Advancement of Science and the American association of Hispanic professionals.

Lastly, Dr. Alva understands the critical need for more bicultural/bilingual mental health care professionals. PNS has a mandate to reach out not only to the general community, but also to the Latino community by having bilingual and bicultural staff in clinical, administrative and medical positions. Dr. Alva and associates understand the attitudes and barriers facing the different ethnic populations in need of mental health services and have a mandate to implement educational awareness and programs to address the identified barriers. PNS physicians are bilingual and bicultural, which are critical attributes in ensuring access to and providing quality mental health services to all of our community.

Back to Staff

Gustavo Alva, M.D.

Psychiatrist and ATP Founder

Dr. Alva is medical director of ATP clinical research (a premiere private clinical research company specializing in neuropsychiatric investigations). He is an Associate Professor in the Department of Psychiatry and Human Behavior at the University of California, Irvine (UCI). He is a forensic psychiatric consultant for the Orange County Superior Court and a diplomate of the American Board of Psychiatry and Neurology.

Dr. Alva received his medical degree from the Autonomous University of Guadalajara (UAG). Residency training was completed at the University of California, Irvine Medical Center in the Department of Psychiatry and Human Behavior, where he served as chief resident during his final year of residency.

Dr. Alva has served as a principal investigator for the past 10 years conducting investigation in a myriad of neuropsychiatric conditions; Alzheimer's and other dementias, depression, anxiety disorders, bipolar disorder and psychotic conditions. As a clinician and investigator, Dr Alva's focus is on the genetics, neuroimaging, and latest treatments available for each aforementioned condition, as well as aspects of ethnicity and their correlation within clinical situations. He has published numerous articles, and presents at both national and international meetings and conferences.

He is the immediate past-president of the Orange County Psychiatric Society. Dr. Alva is also is a member of many professional organizations, including the American Medical Association, the Orange County Medical Association, the California Psychiatric Association, the American Board of Forensic Medicine, the American College of Forensic Examiners, the California Hispanic American Medical Association and the International Congress of Geriatric Psychopharmacology.

To contact Dr. Gus Alva's office directly please call 833-487-2582

Back to Staff

Yvette Elpidio, MSN, FNP-C

Nurse Practitioner

Yvette Elpidio received her Master's degree in nursing with an emphasis on family practice from the California State University at Long Beach. She is Board Certified through the American Association of Nurse Practitioners.

Yvette has been working in the psychiatric field for many years with PNS after completing her MSN degree. Prior to this she worked as a registered nurse for five years before going back to school. She has worked in a varied number of specialized settings which include: telemetry, oncology, medical-surgical, home health and hospice. Yvette has also been instrumental in clinical research having worked for three years as an infusion nurse for ATP Clinical Research.

Valuing education, Yvette teaches nursing students as a clinical instructor for the Cerritos College nursing program.

Yvette's focus is on clinical care looking to provide patients a wealth of expertise, knowledge and a personal warmth in a very real humanistic and holistic approach.

Back to Staff

Sheena Patel, PA-C

Physician Assistant

Sheena Patel, PA-C completed her undergraduate studies at University of California Irvine, earning a Bachelor's Degree in Biological Sciences.  She concurrently performed 4 years of academic research at a UCI laboratory related to Addiction, Drug Abuse, and Associated Effects on the Brain.  Sheena Patel subsequently attained a Master's degree in Biological Sciences from New York University.  She then completed her Physician Assistant training at Long Island University Brooklyn Campus.  She has been a nationally board certified PA-C since 2010.

Her clinical experience is vast and includes work in Internal Medicine, Subspecialty Surgery (Urology, Vascular, ENT, and Plastic Surgery), Pain Management, and Psychiatry.  She has particular interest in Psychosocial Medicine and Addiction Disorders.

She is knowledgeable, thorough, compassionate and cares deeply about the well-being of her patients.

Sheena Patel PA-C is a National Certified Speaker for pharmaceutical medications.

Back to Staff

Tanya Bengali DNP, ARNP, FNP-BC

Physician Assistant

Tanya Bengali, DNP, ARNP, FNP-BC earned a Bachelor of Science Degree in Nursing from the University of South Florida in 2006. Tanya practiced as a RN from 2006 to 2013, specializing in critical care. She graduated from the University of Central Florida Family Nurse Practitioner Program in August 2012 with a Masters of Science in Nursing and became board certified in family medicine in October 2012. She worked in family medicine from 2013 to 2016. She then pursued her doctorate in nursing, focusing on depression screening in primary care, and received her DNP in May 2014.

She is an active member of The American Association of Nurse Practitioners and The California Association for Nurse Practitioners. She has acted as a mentor for many nursing students and also assisted in being a preceptor to nursing students and nurse practitioner students. Tanya is very passionate about mental health and strives to provide health services that place emphasis on both care and cure. Her focus is to help her patients be as healthy and happy as possible.

Back to Staff

Jennifer Sebastian, PA-C

Physician Assistant

Jennifer Sebastian, PA-C received her Bachelor of Science Degree in Biological Sciences from the University of California, Irvine. Knowing she wanted to pursue a career in medicine, she began in nuclear imaging. After attending Loma Linda University, she started her profession in nuclear medicine. In 2013 she completed her Physician Assistant training program at Riverside Community College and received her Masters Degree in Medical Science from St. Francis University.

She has been a nationally board certified PA-C since 2013. She is an active member of both the California and American Association of Physician Assistants. She has clinical experience in Orthopedics, Urgent Care, Addiction and Psychiatry.

Jen is passionate about Addiction Medicine and Psychiatry. This field requires a certain appreciation and a special type of heart. Jen strives toward personalized care and her goal is to give each patient a better understanding and a greater peace of mind.  

Back to Staff

Esperanza Hernandez-Maldonado, LMFT


Esperanza graduated from the California State University at Fullerton in 1998 with a B.A. in Psychology. She obtained an MS with an emphasis in Marriage and Family Therapy from the California State University at Long Beach in 2002.

Licensed as a Marriage and Family Therapist in California, Ms. Maldonado is fluent in both Spanish and English. She has worked in a variety of settings, including inpatient and outpatient Drug and Alcohol recovery programs, psychiatric Day Treatment programs, Schools, traditional office/private practice, and university counseling centers. In addition to individual therapy, she is skilled in facilitating group and couples therapy. She is certified in Play Therapy by the University of California, San Diego.

Ms. Maldonado has had many varied and challenging experiences which have contributed to her ability to provide therapy with compassion, multicultural sensitivity and openness. She served as a trained, certified counselor for the Orange County Trauma Intervention Program (TIP) and functioned as a liaison between law enforcement, hospital personnel and traumatized victims and their families.

While working in elementary schools, Ms Maldonado developed the skills necessary to evaluate, assess and aid both disabled students and students who needed bilingual assistance. She administered standardized tests to students with limited English and became familiar with all aspects of assessment, placement and remediation. She has had intensive clinical training at Kaiser Permanente in their Chemical Dependency unit, and worked at College Hospital with a diverse population of psychiatric patients.

Her therapeutic orientation can be described as cognitive-behavioral with emphasis on family dynamics and existential issues. Her approach to psychotherapy reflects an emphasis on humanistic and existential principles while integrating developmental process and Family Systems Theory in a cultural context. Her practice includes work with adults, children, couples, and families experiencing various personal and relational problems. Ms. Maldonado's broad experience working with people from diverse ethnic and cultural backgrounds in a variety of settings has made her sensitive to the personal needs of others. She is able to balance the need for appropriate boundary setting with the compassion and approachability necessary to do therapy with a wide variety of clinical issues. Ms. Maldonado is committed to using her comprehensive clinical skills and training to help improve the quality of life for her clients.

Back to Staff

Robin Giesen, LMFT


Robin Giesen completed her bachelor’s degree in Psychology at Tulane University, her Master’s Degree in Clinical Psychology at Pepperdine University and post graduate work at the Newport Psychoanalytic Institute where she earned her certification in Dynamic Psychotherapy. She is a licensed Marriage and Family Therapist (MFC 85169) and has been working in the mental health field for over ten years.

Robin received her training at the Straight Talk Clinic, a community mental health clinic in Cypress, Ca where she provided individual, couples and child and adolescent counseling to clients struggling with a variety of issues ranging from depression and anxiety to difficulties in interpersonal relationships. While at Straight Talk she also ran a court approved anger management group, parenting groups, and a process group for teens. She additionally received training with the Brea and Los Alamitos school districts where she conducted cognitive behavioral therapy with students needing help effectively managing their behavior, impulse control, accepting responsibility, resisting peer pressure and coping with the negative effects of bullying and substance abuse. Most recently she trained at Pacific Neuropsychiatric Specialists (PNS), under the supervision of Gustavo Alva, MD, in the treatment of a variety of different mood and thought disorders. Trained in both Cognitive Behavioral and Psychodynamic therapies, Robin draws from both models to assist clients in symptom management, stress reduction, implementing mindfulness techniques, regulating their emotions, and improving interpersonal relationships and overall life satisfaction. A believer in the human capacity for change and growth, Robin’s style is collaborative and supportive as she assists clients in setting and achieving their personal goals.

Robin has additionally completed specialized training in couples counseling thru the Gottman Institute and specialized training in the assessment and treatment of Perinatal Mental Health disorders, (depression, anxiety, OCD, bipolar) thru both Postpartum Support International (PSI) and the Perinatal Mental Health Society. Robin is passionate about women’s mental health and assisting couples and families with difficult life transitions. Robin is an active member of the California Association of Marriage and Family Therapists (CAMFT) and Postpartum Support International (PSI).

Back to Staff

Attention New Patients

The New Patient Packet will provide what you need to get started. To download the New Patient Packet click on the link below

download packet Descargar paquete en español
talk bubble
Yvette is wonderful...

She is sharp, efficient and able to assess my needs. She will not waste your time. I never wait longer than 15 min ( max) to see her. I highly recommend her:) She also is flexible with adding and changing appointments

-Evelyn D. La Habra, CA

talk bubble
Dr. Alex Alva Excellent Doctor...

Excellent doctor, very considerate to patients needs. Listens to patient and family members. From www.healthgrades.com

-Lakewood, Feb 1st 2017

talk bubble
Dr. Alex Alva Great Psychiatrist...

He's a great psychiatrist and was able to get me on medications that changed my life. A God send. From www.healthgrades.com

-J.R.W Irvine, Oct 10th 2016

talk bubble
Dr. Alex Alva Amazing Human...

Amazing human an angel from God! I have seen many doctors no one helped me like he did , the combination of medication and his attitude towards life is what helped me! From www.healthgrades.com

-Monterey, CA May 4th 2016

talk bubble
Dr. Gus Alva is one of the Best Psychiatrist...

Dr. Alva by far is one of the best psychiatrist I have seen. He is very to the point, firm and has great communication skill and comforting language. From www.google.com

-Susan Irvani

talk bubble
Dr. Gus Alva is Awesome...

Awesome Dr. I've had many ups and downs and he sticks at my side through out all these times. I read about all the office issues but very few offices are 100% perfect. From www.google.com

-Sheila Jacobson