about us

Acacia (“Ah-kay-sha”) is a comprehensive mental health management group that helps you flourish in life.  We understand that your mental health is more than just medication and brain chemistry. We believe your mood, thoughts, physical fitness, social connections, desires for purpose, and more all contribute to your mental health.  


As a result, Acacia offers comprehensive psychiatry, therapy, and holistic lifestyle services. Our dedicated care coordinators help guide you through our integrated treatment process. We are committed to helping you flourish: Brain, Body, and Soul.

our team & partners

David Carreon, M.D. 

Psychiatrist, Medical Director


Dr. Carreon is a psychiatrist who has trained at Stanford University.  He has been practicing since 2014 and has clinical experience with TMS and other neuromodulation techniques in addition to general psychiatric and mental health services.  For the past five years, Dr. Carreon has conducted research at Stanford in the Etkin Neuroscience Lab, primarily focusing on the underlying physiology of psychiatric disorders including MDD.  Prior to medical practice, Dr. Carreon received a BS in Civil and Environmental Engineering at UCLA and had an interest in Global Health. Dr. Carreon is Acacia's Medical Director.​

Shauna King Hollis, PMHNP-BC

Nurse Practitioner, Acacia Partner


Shauna is a UCSF-trained psychiatric mental health nurse practitioner with over 20-years experience in the field.  She specializes in ADHD, Anxiety, Depression, PTSD, Sleep Disorders, and Christian counseling.  Shauna provides personalized, compassionate, and holistic treatment plans that integrate medication management, therapy, health promotion, and spiritual well-being.  In addition, Shauna is a wife, mother, and retired veteran of the United States Navy.  She currently practices at Christian Counseling Centers in San Francisco.

Karen Yeh, Ed.M., Psy.D.

Clinical Psychologist, Acacia Partner


Karen is a clinical psychologist who specializes in anxiety, mood disorders, parent-child issues, couples therapy, relationship issues, adolescent & child therapy, stress & behavior issues, life changes, and spiritual/Christian counseling.  She received a Ed.M. in Counseling and Consulting Psychology at Harvard University and has trained in and practices specialized cognitive behavioral therapy called TEAM-CBT.  She is currently based at

the Feeling Good Therapy and Training Center in Fremont.  Prior to therapy, Karen studied Biology at MIT.

Nathan Meng, M.D.

Care Coordinator, Clinic Operations


Dr. Meng is a physician who trained at Stanford University. He most recently served as Chief Technical Officer of Ameda, Inc., a privately-held medical device company in the mother-baby space.  While at Stanford, Dr. Meng was also the Clinical Lead at Embrace, Inc., a startup medical device company also in the mother-baby space. Prior to medicine, Dr. Meng received a BS in Electrical Engineering and Computer Science at MIT and had an interest in medical devices. Dr. Meng run's Acacia's Clinic Operations and Finances.

M. Bret Schneider, M.D.

Psychiatrist, Advisor


Dr. Schneider is a board-certified psychiatrist with over 20 years experience in the field.  He is one of the most experienced TMS specialists in the United States, using TMS to treat depression since 2003. He has operated his private TMS clinic in Menlo Park for over 10 years. Dr. Schneider also serves as Adjunct Professor of Psychiatry at the Stanford University School of Medicine, and has previously completed postdoctoral fellowships in Advanced Psychiatry and Stereotactic Radiosurgery, both at Stanford. Dr. Schneider’s title at Acacia is Consulting Attending Physician, and he will serve on the Clinical Advisory Board.

why acacia?

True Holistic Treatment

We do more than prescribe medications.  Mental, physical, social, and spiritual issues all affect your mental health. Unlike other groups, Acacia treats them all. We provide services for your brain, body, and soul.

Expanding Access

We serve everyone. Acacia is committed to treat our patients effectively and efficiently, so more people have access to our care.  Please contact us for information about Acacia's financial aid program.

Personalized Attention

Acacia Care Coordinators are the foundation of our clinics and meet regularly, in some cases daily, for help and empowerment. They are trained to listen and to guide you through your recovery process.

Advancing Clinical Excellence

Acacia is committed to clinical research, and we partner with scientists worldwide to stay up-to-date and to advance science.  We provide solutions based on the best available neuroscience and technology.

Integrated Continuity-of-Care

Acacia provides exceptional mental health care by directly integrating all providers under one system.  We aim to make your clinic experience from referrals to scheduling to billing as seamless as possible. 

© 2018 by Acacia Mental Health  |  Tel: 650.993.9996  |  Fax: 650.999.0939

Sunnyvale Office:  877 W. Fremont Ave. Ste. J-1, Sunnyvale, CA 94087

Fremont Office:  39210 State Street #200, Fremont, CA 94538

If there is a medical or psychiatric emergency, please call 9-1-1 instead.