Our Team

Dr. Choy and Dr. Yoonas are Board Certified psychiatrists who first met each other in 2007 during their psychiatry residency at Stanford University. The two were selected as Chief Residents in their final year of training, providing them with an invaluable experience to work closely together and develop a strong trusting relationship. Following residency, they co-founded a successful general psychiatry private practice in Silicon Valley, where they continue to see patients.

Recognizing an unmet need in the proper diagnosis and treatment of Adult ADHD in Silicon Valley, they decided to combine their expertise in Adult ADHD and cognitive performance to form the Elite Focus Clinic in 2015. The clinic was cofounded with Phil Boissiere, LMFT, a coaching specialist in Adult ADHD.

At Elite Focus Clinic, they are successfully treating a wide spectrum of patients, ranging from college students, stay-at-home parents, teachers, startup founders, professional athletes, engineers, physicians, lawyers and many others.


Zaakir Yoonas, MD
Executive Director

 Stanford Trained Psychiatrist

To learn more about Dr. Yoonas click here.

Lawrence Choy, MD
Medical Director

Stanford Trained Psychiatrist 

To learn more about Dr. Choy click here.

Elizabeth Quadraccia, PA
Physicians Assistant

 ADHD Medication Specialist

Rachel Barreto, LCSW
Psychotherapist/Coach

 ADHD Specialist

Regina Tyrkas
Office Administrator

 Billing and Support Specialist

Jim Duzak, NP
Nurse Practitioner

 ADHD Medication Specialist